This is a guide intended primarily for friends to help them get an idea of the relative viability of different talents when they're still learning the game. I'm a filthy casual who's never finished a campaign and plays with Jovian Radiation off. I welcome all feedback, especially from those who play very differently to how I do. Make me a convincing argument and I'll edit the guide accordingly.

Class Coordination: it's always worth coordinating with other members of your class to attempt to ensure as many useful and mutually exclusive talents as possible are picked. For example, Engineer's Arms Race and Heavy Hitter provide no benefit if you double up on them, so a crew with two engineers should pick both.

Guidance on bots: notes referring to bots assume a multiplayer scenario where bots cannot be controlled to make use of their talents in an intelligent manner. If you're playing singleplayer and can swap freely between your characters, you're probably better off building them as if they were all real players.

Note: since you're the only role that can't be doubled up on, your mutually exclusive talents are big choices for the whole crew.

Travelling Tradesman: one contender for the best long-term pick, and worth having from the moment you can take it. It'll save you a lot of cash.
Inspirational Leader: a solid talent, and usually makes more sense than Prodigy. Especially nice if people lose skills by dying - if that's an issue in your campaign, this talent never goes out of style.
Veteran: the other contender for the best long-term pick, since the 10% repair speed will still be helping out even when everyone's skills are maxed.
Prodigy: decent, and can help with earlygame skill gain pain.
Bounty Hunter and Logistics Expert: these are almost the same talent, just for different mission types. They're solid if you plan on doing a lot of the mission type in question, but not as generally useful as most of the other Tier 1s.

I usually take Travelling Tradesman and Inspirational Leader. Bots should do the same.

Cameraderie: great if your crew is experienced enough to avoid dying all the time - very strong XP talent for the whole crew. One of the best Tier 2s, if you don't have a lot of deaths. As of Blood in the Water, the XP has been substantially nerfed, but it now also gives physical resistance, so still a great talent.
Emergency Maneuvers: really, really nice in the earlygame, when you don't have high Helm skill.
Gunsmith: great if you don't have any other way of getting hold of weapons, which can be tricky to do early on. Falls off later on when you get better weapons.
Down with the Ship: a nice talent to have - very helpful when everything is going horribly wrong - but I don't prioritize picking it up early.
Sailor with No Name: another nice one to have by the endgame, but not terribly important early on so long as someone's a competent medic. Pipes already do the job of cigars just fine, now that Reaper's Tax isn't a thing.
Steady Tune: very limited usefulness. Can be nice in a pinch if you're trying to deal with psychosis auras from uncontained alien artifacts or Watchers... but if the latter, just shoot it, and if the former, why did you bring a harmonica but not a transport case? The real purpose of this talent is griefing clowns who want to be psychotic.

I usually take Cameraderie and Emergency Maneuvers. Bots should take Cameraderie, and Gunsmith or Down with the Ship.

Gunslinger can wait, unless you're personally responsible for doing the shooting. It's all combat bonuses.
Skipper is great, but everyone's skills will likely end up maxed out by the end of the campaign anyway.
Politician is the strongest early pick, since its XP, reputation, and cash related perks will provide value from the start to the end of the game.

I usually start with Politician, then Skipper, then finally Gunslinger, though I'd consider any order reasonable.

Deputy vs Lone Wolf: do you often end up by yourself in combat situations? Pick Lone Wolf. Do your Assistants do a lot of the fighting or piloting? Pick Deputy. They're both good - I prefer Lone Wolf since I do a lot of fighting and often play without assistants. Bots should almost always take Deputy if there are any assistants to buff, and simply not be left unattended.

Inspiring Presence vs Trickle Down: there are two considerations here. The first is how the skill gain works - if you have the patience to be in the room with people while they're skill-grinding, Inspiring Presence is a *lot* better, since it works even when your own skills are maxed. Swim speed versus walk speed is an ancient debate - speed in water usually matters more, but swim speed doesn't affect scooting speed. I'd usually just take Inspiring Presence, and bots should do the same.

Affiliation vs Your Reputation...: Your Reputation... will get you more money and XP by letting you do more missions. Affiliation is essentially a prerequisite to maxing out rep with one faction without making its opposed faction hate your guts (+50% gain lets you go net positive on rep by doing missions for both factions, since you now gain more with the faction you're working for than you lose with their enemy). I always pick Affiliation, but the extra mission certainly isn't a bad choice - it comes down to personal preference. Same for bots.
Campaigning vs Networking: neither is objectively correct; which saves you more money will depend on your playstyle. If you do a lot of mining and scavenging, and you care about maxing your upgrades, Campaigning will definitely save you more money. If you buy all of your supplies, jump straight from your first submarine to your final one, and don't care about the less impactful upgrades, Networking is the talent for you. If you're not sure, go for Campaigning. Same for bots.

Egghead: an enormous boost to skill gain, and will especially help if you are filling in for other roles on a small crew.
Grounded: the Electrical skill greatly improves your ability to do your job early on. The burn resistance will basically only come up in four situations: your Electrical skill is low and you're trying to do repairs, you stood in the way of someone who was trying to burn ballast flora, you accidentally swam into a volcano, or a fire happened on the ship and you stood too close to it for too long. None of these should be common, but if any of them does seem like a real risk with your crew, 20% burn resistance might save your life.
Remote Monitor: a really strong talent if you manage your reactor manually. I've never been engineer on a large enough crew for this to come up.
Station Engineer: can provide a lot of XP if you're doing a lot of beacon stations. It's just down to luck. Buffed in Blood in the Water to also help you do beacon stations faster, which is nice QoL, but not enough to make the talent competitive if you aren't already doing a ton of beacon stations.
Junction Junkie: the absolute best Tier 1 talent; the skill and XP are fantastic early on, the level 1 junction boxes are a sweet bonus, and the 50% repair speed will be huge in the lategame.

I usually take Egghead and Grounded I recommend Egghead and Junction Junkie, but there aren't really any wrong choices here, even for bots.

Fun With Fission: will make the fuel go a lot further, and is required to craft Masterwork fuel rods unless there's a Loyal Assistant on the crew. Consider coordinating your skill choices with any assistants, since it's far less worthwhile if there is a Loyal Assistant present.
Sample Collection: a staple talent, and will make looting wrecks/ruins/beacon stations/enemy submarines far less tiresome. No crew should be without it.
Submarine Of Things: really great if you use a lot of FPGA circuits (e.g. for custom wiring), and mediocre (but certainly not worthless) if you don't.
Melodic Respite: okay if you're sitting around playing the guitar whenever you're idle, but there's probably something better you could be spending your time on.
Aggressive Engineering: pretty pointless. Just get a real weapon.

I usually take Fun With Fission and Sample Collection, replacing Fun With Fission with Submarine of Things if an assistant can boost item quality. It can also be worth taking all three if you're willing to delay skill tree progression by one level. Bots should probably do the same.

Your skill tree choices provide access to critical crafting recipes, so you should try to consider what the crew needs access to first.
Weapons Engineer is generally not necessary early on, since the top-tier stuff isn't needed for earlygame enemies. The ability to craft depleted fuel ammo for SMGs/revolvers can be very nice if you don't have a security officer, though. Cheap nuclear shells will also make abyss diving more cost-effective, assuming your crew has a railgun and can be trusted to fire nuclear shells without blowing up your own sub.
Electrician is the repair tree, and provides the least useful recipes. I wouldn't recommend taking it first unless you really need the repair talents.
Physicist is usually the best starter tree, simply because of how useful the PUCS is (even after the nerfs, they remain one of the best diving suits in the game - they're the best general-purpose, with Slipsuit, Exosuit, and Abyss Suit competing for specialist purposes).

Arms Race vs Heavy Hitter: if you don't have a Security Officer to craft regular ammo, take Arms Race. Otherwise take Heavy Hitter to boost everyone's repair speed. Same for bots.

Pyromaniac vs Unlimited Power: Unlimited Power is the better general pick, especially if you don't have a Loyal Assistant to boost item quality. If you do have a Loyal Assistant, and you really want bonus burn damage or the ability to craft Flamers to get them at Masterwork quality, Pyromaniac is a reasonable choice. Bots should almost always take Unlimited Power.

Buzzin' vs Cruisin': a deceptive choice. Cruisin' looks like it should just be better, since max output is rarely an issue with multiple fuel rods. What the game doesn't tell you is that increasing max output also increases fuel efficiency, since the fuel consumption of a reactor is calculated based on what percentage of max power it's running at. So 10% max power is also 10% fuel efficiency. Which one is better? Debatable. I do a lot of mining, so I prefer the max output since it matters more once you have so much uranium you'll never run out. But Cruisin' is very reasonable too.

Engine Engineer: great long-term talent - 20% max engine speed is very hard to say no to.
Salvage Crew: wreck salvage is very lucrative, so this can be a great investment if your crew likes to do them. Still, these missions don't show up in the first sector, so it probably shouldn't be your first talent. Gives swim speed and physical resistance while inside wrecks as of Blood in the Water, which is a small but notable buff to an already-good talent.
Machine Maniac: [s]not very much XP, and can be a pain to pull off. Not terrible, but low priority.[/s] nice talent as of Blood in the Water - the bonuses are good, but it can be tricky to find enough mechanical devices to repair. (Currently possible to exploit this by plasma-cutting and fixing doors, if you have nothing better to do.)
Ballast Denizen: do you ever end up actually passing out from oxygen deprivation? It has some uses if you do away missions and aren't great at oxygen management, but asphyxiation deaths are rare - there simply aren't enough situations where it'd kill you and the pressure wouldn't do it first.
Multifunctional: niche earlygame talent, for when a crowbar is the best weapon you have access to. Still not great.
Safety First: not the best talent since the Safety Harness uses the Diving Suit slot, but if you have people who don't care about pressure (typically from controlled husk infections), the resistance to getting pushed around by water flow can be quite nice for getting around the submarine when it's taking damage. Still not competitive with the good talents, but coming back for it later wouldn't be crazy.

I usually pick Machine Maniac and Engine Engineer, although if you do a lot of wreck salvage, Salvage Crew is a reasonable choice. Bots should do the same.

Pump N Dump: the uncontested best long-term talent, this really helps when the sub takes damage.
Ironman: skilled combat players will have a lot of respect for the Iron Helmet and Makeshift Armor. Not very useful if nobody has a crazy build designed to let them survive outside without a diving suit, since Makeshift Armor and Diving Suits can't be used at the same time.
Oiled Machinery: really nice quality of life talent, practically auto-pick if you don't want Ironman.
Retrofit: convenient in the short term, but completely superceded by Iron Storm once you have it.
Modular Repairs: I've never had so many spare resources and wanted fast repairs so badly I found the repair pack an attractive option. I would consider this the worst Tier 2 talent.

I usually pick Pump N Dump and either Ironman or Oiled Machinery, depending on my crew. Retrofit is also a reasonable choice, if you're in a rush to take an earlygame submarine into deep waters and want to shore up the hull. It can be worth going back during or between skill trees to pick up Ironman/Oiled Machinery/Retrofit if you didn't grab them at the start. Same for bots.

Scrapper is almost objectively the correct skill tree to take first. Between the resource benefits and Iron Storm, it provides more value the sooner you get it.
Machinist is a decent choice - Fixfoam Grenades and Portable Pumps can do a lot to save a submarine which has taken critical damage if you know how to use them effectively. But they can be expensive in the earlygame, so I wouldn't recommend it as a first tree.
Brawler looks at face value like a personal combat tree, but Exosuits will provide considerable value to the crew as a whole. You can take it earlier if you're doing a lot of melee fighting, but it's probably still not as useful in the beginning as Scrapper.

I usually take Scrapper, then Brawler, then finally Machinist - my experience using Fixfoam Grenades and Portable Pumps is limited, so I don't get as much value out of them as some people might. Bots have totally different logic which leads to similar conclusions - I usually still have them go Scrapper first (but only for Tool Maintenance and Iron Storm), then Brawler (for the Exosuit recipe), then finally Machinist (for repair speed, fixfoam, and defense bots).

Mass Production vs Residual Waste: don't be fooled by the bigger percent number. Mass Production is a 40% chance to not consume *1* ingredient item, while Residual Waste is a 20% chance to double *all* deconstruction output, which stacks with Miner. You might get some value out of Mass Production if you're crafting a lot of items which use a single, expensive ingredient (such as physicorium harpoons), but it won't benefit other people's crafting (and talents affecting crafting quality may mean you shouldn't be crafting everything yourself). Residual Waste is usually just better. It's also worth noting that you can use Residual Waste to create certain materials - if an item refunds its full cost when deconstructed, you can use it to duplicate those materials. If it refunds partial cost, you're effectively transmuting the materials it doesn't refund into the ones it does. Bots can't make use of either. With the Blood in the Water update (coming next week as of this edit), bots can be ordered to deconstruct items, so they should now always take Residual Waste.
Scrap Savant vs Tool Maintenance: if there is or will be a Loyal Assistant, take Scrap Savant. Otherwise, take Tool Maintenance. Scrap Savant is way less useful, but Tool Maintenance is completely superceded by Loyal Assistant. Bots should generally take Tool Maintenance, both because it's excellent and because they don't loot containers in wrecks.

Quickfixer vs Tinkerer: a matter of personal taste, but I generally prefer Tinkerer. Quickfixer will get you more skill gain, and helps you repair things faster when everything's falling to pieces, but it's rare for multiple mechanical devices to need repairs at once. Bots are probably slightly more efficient with Quickfixer, since they automatically know where all broken devices on the sub are at all times, so delaying deterioration is less useful to them. Tinkerer will be better for most players for most of the game, but Quickfixer is probably stronger in certain endgame content, since the extra durability won't help against EMPs.

Heavy Lifting vs Mudraptor Wrestler: an absolute non-choice, I can't imagine why anyone would take Heavy Lifting. Just use a cargo scooter if you need to transport stuff. If you've got an artifact, just ragdoll and let someone else carry you with a scooter. 10% physical resistance and 50% more melee damage to mudraptors is amazing stuff, and never worth passing up for such a marginal alternative, even on bots who rarely do combat.
Berserker vs Foolhardy: Foolhardy is usually better, since it has wider applicability beyond just melee, and the extra physical resistance will probably let you get in an extra swing or two before you go down even if you are in melee. Bots should always take Foolhardy.

Stayin' Alive: extremely important, this talent can save lives when less skilled crew are trying to do CPR in your absence (or to save your life). A must-pick.
Example of Health: fantastic talent. Your job is to keep other people alive, and you can't do that if you're dead. Simple as that.
Self-care: a slightly less powerful Example of Health, with extra utility in the long run since it makes combat drugs more effective on you.
La Resistance: functionally a slightly less powerful Self-care, though it doesn't reduce resource consumption, just allows you to spam more drugs on yourself without running into addiction issues.
Nobody Important Dies: [s]a decent XP talent, completely overshadowed by the other options. There are just too many other good Tier 1 talents to justify taking this.[/s] reworked - still a decent talent, but now geared towards helping you keep non-assistants alive at the cost of assistant life expectancy. It's slightly better than it looks (+10% medical item effectiveness means stabilozine can now eventually cure all non-cyanide poisons if used correctly), and is probably a net positive unless your crew has large numbers of combat assistants, but still not as good as other talents at this tier.
Health Insurance: [s]far too specific. If you can't take Nobody Important Dies, you definitely can't take this.[/s] now completely reworked, and still too weak to justify taking - the cash payout is small (easy to activate via controlled self-suffocation, but hardly worth it), and the 10% discount is nice but not worth passing up powerful talents for.

I usually take Stayin' Alive and Example of Health. Bots should do the same. Virtually everything other than Health Insurance is worth coming back for once you have the important tree talents.

Fireman's Carry: practically mandatory, this allows you to carry downed people fast enough to escape pressure death, drowning, or angry monsters. Also makes transporting corpses more convenient (either to get them out of the way or feed them to petraptors).
Don't Die On Me: excellent talent, turning CPR from a maybe into a yes and allowing you to quickly revive people from downed. You can use medication to revive people instead, but it's less efficient.
Medical Companion: the auto-injector headset is extremely nice, and can easily save lives with a bit of morphine or fentanyl in it.
No Pressure: Pressure Stabilizers are very powerful drugs, but most useful in the hands of expert players, and too expensive to use much in the earlygame. Hard to justify taking at the time, but very much worth going back to pick this up later.
Blood Donor: decent, but completely overshadowed by other talents. Just craft your blood packs like a normal medic, or use saline/alien blood. Nerfs to saline/alien blood have rendered it more competitive. (Playmaker-M1 points out it saves on Stabilozine for crafting and you can just sell the blood packs if you don't need them, but I still don't think it competes with other talents at the same tier.)

I usually take two of Fireman's Carry, Don't Die On Me, and Medical Companion. It can be well worth going back for the other before you've finished every tree, as well as picking up No Pressure when you have a spare skill point. Bots should take generally take Medical Companion and No Pressure, since they're not competent at actually providing medical treatment.

Xenologist is a strong first choice, since you won't be able to loot Genetic Material until you have it, and Genetic Material is something you can almost never have too much of. You'd probably rather not be locked into the rest of the tree, but that's life.
Medic is also a reasonable first choice, since it makes you and assistants significantly better at providing medical treatment. I don't rate it as highly as Xenologist, but it's not bad, and its talents are almost guaranteed to save multiple lives over the course of a campaign.
Chemist is the weakest early pick, since it primarily provides expensive crafting recipes. Lab Contacts and the ability to craft Europabrew are somewhat useful early on (as Europabrew is a universal antidote to poisons), but poisons are generally not enough of a problem to justify it over the others.

I usually take Xenologist, then Chemist, then Medic. If you have two doctors, I recommend one going Xenologist->Medic->Chemist and the other going either Chemist->Medic->Xenologist or Medic->Chemist->Xenologist. Bot medics should go Chemist first (the other trees aren't terribly useful on them).

Bloody Business vs Gene Splicer: if you're ever planning on doing genemodding, take Gene Splicer. If you're not, why did you take Xenologist at all? Bots should take Bloody Business, though neither is very useful to them.
Blackmarket Genes vs Gene Tampering: Gene Tampering is generally better, but Blackmarket Genes does give you some extra cash and make it easier to get high-tier genemods sooner. It's the same decision for bots (though if your only medic is a bot, genetic material won't be of as much use to you since your bot can't refine it, so I'd still recommend Gene Tampering).

Emergency Response vs Medical Assistance: Emergency Response is generally the superior choice, since it buffs your move speed, and having assistants able to drag people out of danger is useful. If your assistants need medical skill, just let them craft bandages.
Dr. Submarine vs Vitamin Supplements: on the one hand, Dr. Submarine enhances the effectiveness of combat drugs, and 25% more effective drugs might allow you to administer more opiates without overdose/addiction (I have not tested whether it also increases negative effects of drugs). On the other hand, Vitamin Supplements only costs you a bandage or a bottle of pomegrenade per crew member per mission (basically free once you're past the earlygame), and they're suddenly far more likely to survive long enough to treat themselves or crawl back to the medic if they get injured far from you. Dr. Submarine will also theoretically mean you use 25% less medical items, but this is usually not important in the lategame. On balance, Vitamin Supplements is probably more likely to save lives, assuming you can get your away team to stand still for long enough to bandage them up before they leave.

Delivery System vs Lab Contacts: if you're a recipe completionist, or you use syringe guns, take Delivery System. Otherwise, Lab Contacts will save you both time and money.
Super Soldiers vs What A Stench!: I don't rate poison and acid very highly, but I do respect combat drugs, so I'd consider Super Soldiers the natural choice.

Physical Conditioning: one of the best talents in a strong lineup. The speed and oxygen low resistance will both help to keep you alive.
Swole: another great one - it's most valuable if you like to melee, but 10% health is great regardless.
First Aid Training: nice when you get sent on away missions without a medic, and 35% medical item potency is very nice if you end up using combat drugs in the endgame. It will also enable you to be treated for all non-cyanide poisons with stabilozine (so long as the poisoning isn't in advanced stages), which might save your life and will definitely save resources. Also very strong if the team is missing a dedicated medic, or the medic is a bot.
Buff: similar functionality to First Aid Training (buff duration is good for combat drugs and opiate addiction resistance helps you avoid the consequences of self-medicating in the absence of a medic). Not quite as strong, but still good.
War Stories: [s]easy to activate, but 80 XP is hardly worth it compared to some of the other talents.[/s] formerly an XP talent, this is now useful for training the Weapons skill of yourself and others. And it barely does that, so I can't recommend it.
Protect and Serve: [s]escort missions aren't rare, but they aren't common enough to make this competitive in a pool of other strong talents.[/s] now that this multiplies reputation gain as well as XP, it's an amazing talent if your crew cares about maximising rep. It might look like it's more for the team than just for you, but with this kind of incentive to do escort missions, it's likely you'll be doing a lot of them, so you'll personally benefit greatly from the XP multiplier.

Prior to Protect and Serve being buffed, I would usually pick Physical Conditioning and Swole, or replace one of them with First Aid Training if there's no dedicated medic. Now it's probably worth replacing one of them with Protect and Serve (they're both good, so it comes down to personal preference on which one you can live without). The same talents are still good on bots.

Weaponsmith: probably the best in another batch of really strong talents, this is mostly notable for the +1 quality on weapons crafted, though riot shotguns and SMGs are also really good earlygame weapons. You can consider skipping this if your team has an assistant who's planning on taking Loyal Assistant, but it will hurt to be unable to craft your own shotguns/SMGs.
Munitions Expertise: another very strong talent, this grants access to a far larger pool of ammo by enabling you to craft it. You don't need it if an Engineer is taking Arms Race, but as Arms Race is mutually exclusive with a better Engineer talent, there's a reasonably high chance your crew will want you to take this.
By the Book: absolutely amazing if you can pull it off, this turns abandoned outposts, pirate beacon stations, and pirate subs into a huge haul of money and XP for the whole crew. It only works if your team cooperates, and people know how to capture NPCs nonlethally, but the rewards are immense.
Don't Push It: I haven't played enough with shotguns to rate the effectiveness of explosive slugs, but evaluating it for the bandolier alone: it's competitive, but only if you already have the ability to craft whatever guns and ammo you need. +15 weapons and +25% fire rate is nice, especially since it applies to ship's guns, and it now only takes up the toolbelt slot (making it quite attractive for security officers). It's a nice talent to have in the long run, if only to be able to have bandoliers for your gunners, but it's generally more important to make sure you can craft guns/ammo than get some nice buffs for using them.
Bootcamp: a very solid XP talent, but struggles to compete with the incredibly important crafting talents it shares a tier with. Has now been nerfed to instead provide Weapons skill once you've gained 5 talent points from it, so now even less competitive. Still quite good, just not as important as the rest.

I usually take Weaponsmith and Munitions Expertise, but By the Book is strong enough to justify replacing Munitions Expertise or even taking all three before continuing to trees, so long as your crew is willing and able to capture live prisoners. Don't Push It is also a valid alternative to By the Book, if you don't want to bother with live NPC capture. Logic for bots is essentially the same (though a crew without player Security Officers is less likely to be able to fight well enough to take prisoners, so you're less likely to want By the Book).

Frogman gives you abilities which are useful on away missions, and you'll probably be expected to do a lot of those as Security.
Enforcer is oriented more towards raw combat power. It'll make you almost universally better in a fight, but doesn't bring much in the way of crafting recipes.
Gunner makes you better at ranged combat, and is the only tree which makes you better on the ship's guns. It also offers a lot of crafting recipes for guns and ammo, which can be nice if you skipped Munitions Expertise and/or Weaponsmith.

There isn't a clear right choice for first tree. Pick what you most want to be better at - diving expeditions, face-to-face combat (particularly on the sub), or firing guns. I usually take Frogman or Gunner first, and Enforcer second. Bots should usually take Gunner first, unless you really want the recipes from Frogman early.

Scavenger vs Slayer: do you plan on using a harpoon coil rifle as a primary weapon into the endgame (probably with physicorium harpoons)? If so, take Slayer. If not, take Scavenger - it's generically very useful, just doesn't help you with combat. Bots should take Slayer.
Daring Dolphin vs Easy Turtle: Easy Turtle is generally better, since Daring Dolphin doesn't affect scooter speed. Daring Dolphin is decent if you plan on using a Slipsuit, but 20% damage reduction is usually still better.

Beat Cop vs Stonewall: these are both good talents, and neither is wildly better than the other - one offensive, the other defensive. I favour Stonewall because it's more likely to help you in a losing situation, whereas Beat Cop is more likely to make a fight you're already winning go smoothly... but Beat Cop will help you a lot with capturing enemies alive, which you can get paid a lot for if you took By the Book. Bots should take Stonewall.
Crusty Seaman vs Inordinate Exsanguination: another offense-versus-defense choice, but in this case I tend to favour Inordinate Exsanguination. It makes you a lot more lethal, and applies to attacks made with the ship's guns as well, which often already inflict a high amount of Bleed. Crusty Seaman will do a lot to keep you alive, though, and is a great choice if you spend a lot of time on away missions, or if you don't trust your medic to do their job. Bots can really take either, too - it just depends whether you want them to be better gunners or have higher survivability.

Commando vs Tandem Fire: I haven't experimented much with Commando, since I initially assumed it didn't work in water. This is not the case - holding your crouch button in water will activate it. I still rate Tandem Fire a little higher, since 20% damage on two ship's guns is a really nice talent, but if you always end up doing EVA and you're not needed as a gunner, Commando is a reasonable pick.
Extra Powder vs Gun Runner: neither of these is hugely impactful, but Extra Powder comes out a fair distance ahead. It'll boost the damage on railgun and exploding coilgun shells you fire (as well as grenades, if you use those), and allow you to craft masterwork explosives to pack into your railgun shells even if you don't have a Loyal Assistant. Even on NPCs, Gun Runner doesn't really stack up favorably - movement speed while carrying ammo is a nice quality-of-life feature, as is movement speed while aiming, but neither is as impactful as boosting the damage of the gun you use to kill giant sea monsters.

Skedaddle: the most useful option in the long term. Movement speed is fantastic, and when you're getting hit is often when you need it the most.
Crew Layabout: great if you're willing to sacrifice your own effectiveness for others' gain. Less so if your crew expects you to do the majority of repairs/crafting.
Starter Quest: the premier XP talent, and also levels your skills really fast. It's one-time only, but the XP and skill gain are both huge, so it's well worth taking (it'll be a very long time before any other XP talent pays out as much in total as this one will immediately).
Playing Catchup: incredibly impactful if you're joining a game very late, and others are already far ahead in levels, but otherwise not very useful.
Mule: seems okay, but not especially useful unless you spend a lot of time playing quartermaster. Note that this only applies to crafting materials (i.e. minerals), not medical items, ammo, oxygen tanks, etc.
Mailman: will never compete with Starter Quest or Playing Catchup for XP, but if you're really pressed for money or care more about levelling up than having useful talents now, it might be for you.

I usually take Starter Quest then Skedaddle. Bots should usually take Playing Catchup (since bots are typically hired at least several missions after the start of a campaign) and Skedaddle, with Crew Layabout as a reasonable option if you're not using them for repairs. If you're joining a game several levels behind other players, take Playing Catchup instead of Starter Quest - you won't regret it.

Peer Learning: one of the strongest XP talents in the whole game, since it applies to everyone who's tied for lowest level.
Inspiring Tunes: fantastic for crafting if your crew is willing to coordinate. +15 all skills is effectively moving the +1 item quality point from 100 to 85, which will translate to getting excellent/masterwork equipment well ahead of the curve.
Jenga Master: whether this one matters to you will come down to whether you hoard enough stuff on your sub for storage space to ever be an issue. If you do, it's very nice.
Bag It Up: gives you access to bigger toolbelts with bigger move speed reduction. They're nice to have, but not super important.
Indentured Servitude: solid if you have a large number of assistants, but otherwise a subpar talent.
Revenge Squad: insanely situational, and only likely to come into play if your crew was about to die to getting boarded by mudraptors or something. Generally not worth it if you have competent fighters - game-overs are more likely to happen by the sub hitting crush depth or getting stuck in a volcano than to physical damage. I would consider it the worst Tier 2 talent.

I prefer Peer Learning+Inspiring Tunes, though Jenga Master and Bag It Up are reasonable alternatives. Bots should usually take Peer Learning and either Bag It Up or Indentured Servitude (I'm not sure whether they use Jenga Master properly).

Apprentice is the strongest generalist pick. It offers the most value to the whole crew, and gives you an entire bonus skill tree when you reach the top.
Grayshirt is the pick if you're definitely going to die a lot, and you just want to be expendable.
Clown is never really the correct choice to take first unless you desperately want to put the medic out of their job with True Potential, but I respect people who do it anyway.

I usually take Apprentice, then Clown or Grayshirt, depending on whether I'd rather have The Waiting List or True Potential first. Bots should always take Clown last; it's simply not useful to them.

Non-Threatening vs Tasty Target: generally speaking, pick Tasty Target if you want to do combat or Non-Threatening if you don't. Tasty Target will make you a better fighter, and help protect the rest of the crew, but Non-Threatening can enable very risky plays, such as solo away missions when enemies are known to be present, since you can just self-inject fentanyl and ragdoll in the knowledge that you will probably survive. NPCs should take Tasty Target if you don't mind them being prioritized by enemies.
An Apple A Day vs Insurance Policy: pick An Apple A Day if you die a lot (or want your dying to have no penalty besides the loss of what you're carrying), or Insurance Policy if you intend to die rarely or not at all, and can accept full skill loss on death. NPCs should always take Insurance Policy.

Chonky Honks vs Psycho Clown: Psycho Clown is a far stronger talent, if you're interested in melee and willing to put up with constant psychosis. Chonky Honks is highly situational, but if you really want to go around dual-wielding a ceremonial sword and a bike horn and using Chonky Honks for damage mitigation, don't let me stop you. (It's probably still worse than Psycho Clown.) Neither is really useful to bots (you can give them a bikehorn in their off hand so they honk it when they attack, but they're not going to use it intelligently, and they're not good enough in combat for the melee speed to provide much value).

Journeyman vs Logistics System: if you value what Logistics System offers, pick it, since you won't get that kind of functionality elsewhere. If you don't, Journeyman is an easy choice. I prefer Logistics System, since +10 to your primary skill isn't a huge deal in the long term. Bots should take Journeyman, since only the character with Logistics System can place the shelves, and they won't do it.
Loyal Assistant vs Treacherous Scum: as insanely good as the +20% repair/weld/skill gain boost is, Treacherous Scum is still the less useful talent. The thing to bear in mind about Loyal Assistant is that it affects *all item quality*, while all other item quality talents affect only a few specific items. Pick Loyal Assistant, and make sure you or someone whose job matches your apprenticeship is responsible for crafting, and all your gear can be Masterwork forever. The same still applies to bots, just make sure a player who matches their apprenticeship is doing the crafting.

Picking Your Apprenticeship: when considering what job to take an apprenticeship in, you should be thinking about Graduation Ceremony, and what skill tree you're hoping to get from it. Here's a breakdown of your options.

Captain: it's really hard to go wrong with this one. None of the options here are bad.

• Gunslinger: Yes. You're now a terrifying combat character with Lone Wolf and Drunken Sailor making you virtually immune to stuns, Deputy keeping your Weapons skill up even if you die, and Quickdraw and Big Guns making you terrifying with a handcannon. (Do note that Endocrine Boosters can give you Lone Wolf, so you don't need to go Gunslinger to get that one.)
  
• Skipper: Maybe (though it's probably the weakest in the long term). You now provide both of Inspiring Presence and Trickle Down, where normally you'd only get one (plus everyone gets a free level).
  
• Politician: Yes. You're now an XP printer, plus you get all of the mutually excluive talents to help with faction reputation, prices, and missions.

Engineer: I wouldn't recommend it, especially if you have an engineer on crew to unlock recipes.

• Weapons Engineer: Maybe. Gives you a modest boost to Weapons, but otherwise just unlocks crafting options. You can put a bot assistant in this if you really want to be able to make both hardened tools and depleted fuel small-arms ammo.
  
• Electrician: No. It's slightly more useful - you'll be better at repairs, better at setting things on fire, and you'll get the Lightning Wizard passive, which is decent. But it's just not competitive.
  
• Physicist: No. A minor reactor boost, better melee with crowbars, and a few recipes. Not enough to be worth it.

Mechanic: decent, with a 1/3 chance to roll some really good combat talents.

• Scrapper: Maybe, if you don't mind being responsible for all mining, fabrication, and deconstruction forever, since you are now better at it than anyone else can ever be.
  
• Machinist: No. Makes you absurdly good at repairing mechanical devices (and the hull), but doesn't offer much else to a crew which already has a mechanic, and mechanical device repairs are rarely a struggle.
  
• Brawler: Yes. One of the best combat skilltrees in the game, giving you weapons skill, melee damage, physical damage resistance, and movement speed while in an exosuit.

Medical Doctor: better than Engineer, but otherwise probably the weakest option, unless you don't have a dedicated player doctor. Your odds of hitting a good tree are poor, and even the good tree doesn't make you as overwhelmingly better at medicine than doctors as combat trees can make you better at combat than normal combat personnel.

• Xenologist: No, unless you really want access to genemodding and don't have another doctor who can do it. The only value you get over 1/3 of a real medic is having access to both Blackmarket Genes and Gene Tampering, and that's very low value compared to other things you can do with Graduation Ceremony.
  
• Medic: Yes, with the proviso that if you do this, you really are a dedicated medic. As in, you're better at it than a real medic can ever be - your medical skill is far higher, and you have mutually exclusive talents which a normal medic can't take both of. The only downsides are that your CPR isn't as innately strong as a real medic's (though high Medical skill should offset this, and you have True Potential if you need it), and Miracle Worker on other medics won't be able to save you from death.
  
• Chemist: No. The only benefit to you taking this instead of a real doctor is that you'll get a bunch of mutually exclusive recipe talents, and recipe talents are always a weak reason to choose your apprenticeship, since multiple people of that class can just coordinate and take both anyway (just hire a bot if you don't have multiple real players of that class).

Security: there's no bad skilltree here if you want to do combat, but what skill tree you roll will have a lot of impact on what sort of combat you're good at. I'd consider Enforcer to be the best of the three, but the others are far from worthless.

• Frogman: Yes. Makes you very good at fighting in water, especially with harpoon coil rifles.
  
• Enforcer: Yes. An incredibly strong generalist combat tree, increasing your stun and damage output and giving you increased survivability, especially against rapid attacks. (Honorable mention to Implacable, a talent which can very easily save your life if you would otherwise be knocked unconscious in combat.)
  
• Gunner: Maybe. Makes you excellent with guns and explosives, but does nothing for your melee attacks or survivability.

The Endocrine Booster drug gives you a random talent selected from a pool, excluding those naturally available to your own class. Here is an overview of talents available, sorted vaguely into categories of "generally good" and "situational only". Each is marked with the class which *cannot* receive it from Endocrine Booster (since it is a natural part of that class's talent tree).

Good:

• Mudraptor Wrestler (Mechanic): 10% physical resistance is effectively 10% health for most purposes, and +50% melee damage to mudraptors is no joke, given they're some of the scariest enemies that can get on board the sub.
  
• Skedaddle (Assistant): 10% move speed, increasing to 30% if you take damage. Movement speed is really, really hard to oversell.
  
• Physical Conditioning (Security): 10% move speed and 30% low oxygen resistance. About as good as Skedaddle on balance - that is to say, very good.
  
• The Waiting List (Assistant): die 75% slower while in bleedout. If you're ever bleeding out and dying of anything other than pressure, this is very likely to save your life.
  
• Lone Wolf (Captain): 20% physical damage resist, stun resist, and melee damage. Situational but incredibly powerful if you ever go on solo missions.
  
• Down with the Ship (Captain): a surprisingly useful generalist talent for disaster scenarios - swim speed and hull repair speed are good on almost anyone, and when your submarine is flooding is the perfect time for it.
  
• Grounded (Engineer): if you do combat (particularly in alien ruins), burn resistance has some usefulness. If you don't, it's still nice against, random friendly fire, volcanoes, and electrical accidents, though none of these should be too common. The +10 electrical engineering is handy if you ever do repairs, too.
  
• Example of Health (Medical): 20% max health is a huge survivability boost. This is always great.
  
• Dr. Submarine (Medical): if you ever use medical items and you're not the medic, 25% bonus effect will go quite a long way.
  
• Swole (Security): 10% max health and 25% melee power. Not as good as Example of Health unless you do a lot of melee, but well worth stacking on top to improve your odds of survival.

Situational:

• Revenge Squad (Assistant): +30% physical damage resistance for crewmates if you die. It might very occasionally save your crew from a dire situation, but you're still dead.
  
• Egghead (Engineer): skill gain speed isn't too important in the endgame, but it's nice until then, and on people who die a lot. +100% is a lot.
  
• Prodigy (Captain): +50% skill gain speed just isn't as good as 100%. It's okay, but nothing to write home about, unless you die a lot.
  
• Unstoppable Curiosity (Engineer): pretty bad. Crowbars aren't a good enough weapon for bonus damage with them to be very useful. Forcing doors faster is nice quality of life if you do a lot of wrecks/alien ruins, but not powerful.
  
• Ballast Denizen (Mechanic): hold your breath for 50% longer. Death from asphyxiation is unusual but not unheard of.
  
• Miner (Mechanic): unless your team is missing a mechanic, or your mechanic hates mining, this is a complete waste of time.
  
• La Resistance (Medic): only relevant for characters who see a lot of face-to-face combat, since addiction resistance is for people who use combat drugs or get opiates spammed on them. Still, 50% addiction resistance is nothing to sneeze at.
  
• Beat Cop (Security): inflict +25% stun, or +50% against monsters inside the sub. like La Resistance, it's very much a combat talent. Unlike La Resistance, it's not useless for gunners, since ship's weapons also inflict stun. Solid if you do combat, pointless if you don't.