After people finding out that I use the controller they ask me two questions:

Why? and How?

Your first answer is because I have little baby hands and I don't have the reach to hit all the keys I need. I do play games like TF2 with a keyboard + mouse but you will see me miss keys ALOT.

First off the game will lock the controller on or off from the title menu, for some reason, so you must start the game with the controller to be able to use it. Also you can't switch back without restarting the game.

Yeah so the controller isn't impliement well, to say the least.
But if like me you have little baby hands or something else wrong with your arms/hands/fingers it's good to learn to use the controller. Plus they are cheap, mine only cost me $50 for brand new corded 360 controller. So no batteries and I just have to lean back in my chair and relax.

This is the loading screen you get when you have the controller enabled.

It's unclear but you HOLD down left stick to run, and press the right stick to melee, holding it down to charge the attack.
Also the D-pad layout annoys everyone:
Up is Push-to-Talk
Down is Toggle Gadgets (laser, flashligh, etc) and hold to use the Bi-pod (if equipped)
Right is Toggle Fire Modes (single or multifire) not available on all weapons.
Left is throw Grenade.
Here is the problem: it's rediculously easy to hit 2 directions at once with a standard 360 D-pad.
Meaning when you try to use Push-to-Talk, you might throw a grenade as well. It really sucks when it happens in stealth.
The best thing to do is to practice pushing towards the right side of the D-pad when using Push-to-Talk since you'll just switch fire modes.

Still the rest are pretty standard and easy enough to learn/remember.

In the game menu there is an option for Aim-Assist, what it does is very simple.
Since the controller takes a little bit of time to swing around and line up targets, it's very usefull but has it's advantages and disadvantages. It works by auto-aiming at any close enemies when you look down the sights. It does go for the body shot alot more but that's fair. The main weak point to this is accuracy, since it has a nasty habit of hitting corners and locking onto shields or tans.

Another thing is that you can't crouch-jump, so you can't jump out of the windows in places like the Methlab for better or worse, as well as doing thing like Hot Lava that require platforming.
Personally I like moving around with the controller more, it's a little smother and it's harder to miss keys and so on.

Still aside from that there isn't too too much different, most of it is adaptation.

Since you're using a different method of playing, you'll need to look over your weapons and builds.
This is kinda vague, since I don't just want to list all my personal preferences, So basically all you need to know is that you need to "compensate" for the disadvantages of the controller.
The main one is accuracy. Meaning you should consider using more Assault/Submachine guns and Shotguns, since accuracy isn't as much of an issue with them.

Both armour and dodge builds work but you need to test them before jumping in to higher difficulties.

I've heard my fair share of myths around the controller so I'm more than happy to debunk them here.
(I'll add to this when people message me with more, trust me they will)

Myth: Using the controller makes the game easier.
Completely not true. If anything it's harder due to the lack of accuracy. But I've heard people say even having it plugged in makes the game easier and it's all wrong. With or without the game's difficulty/spawn rate will remain the same. The only truth in this is that it does make certain achivements harder, but that's due to trying to move/aim with the controller.

Myth: You can't do DW with the controller.
I can. Plus I know I'm not the best player in the world. But that's not the controller.

Myth: The controller isn't sensitive enough.
The sensitivity controlls are in the menu.

Myth: The controller has input lag.
I use a corded controller and I've had no input lag. Your sensitivity may be too low or if you're using a wireless controller there may be interference. Any other wireless device can do it.

Myth: You can aim properly/accuratly with the controller.
Tbh I have a Wacom drawing tablet and if I really wanted to I could play with that. It's down to practice and having the settings set up correctly for you.

People keep giving me alot of ♥♥♥♥ for using the controller, but it's what I'm use to and how I've always played and will keep playing.
The controller is great if you have a physical/neurological condition, or little baby hands like mine, that makes it difficult to use a keyboard and mouse. As well as making it much easier to kick back and relax and play.

The one issue I've found is with the driving. It's do-able but I find myself getting stuck alot on tight turns. So I just have to ride shotgun. Driving did get changed but it's still a little fiddly.

Still there's not much else to add, so just plug it in and go.