There's a free update to ArtRage 4 coming soon that includes 64 bit support for larger canvases and faster painting, grid overlays as guides layout and proportion, live stylus tilt support in the pencil tool, and a bunch of other tweaks and enhancements.

You can find out more about the free 4.5 update here: http://www.artrage.com/artrage-4/free-update/

Note for Windows XP Users: Unfortunately the technology we're using in 4.5 isn't compatible with Windows XP. We intend to keep an original 4.0 version available for XP user compatibility but the new features will not be available.