I recently installed the latest GIMP (from a third party source, since Canonical doesn’t think tablet support in graphics editors is important). Yes, GIMP 2.8 supports Wacom tablets! Woohoo!
You get a couple different settings involving pressure sensitivity, and several tools are affected by it. You can now paint using your tablet directly in Gimp, which is very nice.
Certainly though, while Gimp excels at being a powerful image editor, it was never aimed at efficient digital painting; it simply doesn’t provide enough brushes and doesn’t have a stylus-friendly colour selector among other things. Its UI is also not made to be used with a tablet. Still, you can do basic digital painting directly in Gimp now.
I find MyPaint to be an awesome digital painting app. It’s made to be used with a tablet and provides a large selection of very nice brushes, user friendly colour picking, endless canvas that can be rotated, basic layers etc. Very straightforward, brilliant digital painting app that is perfectly complemented by Gimp 2.8 with its new tablet support.
So painting wise, between those two programs, I’m a happy camper.
I made this in MyPaint (background in Gimp) inspired by the default KDE 4.8 theme. Unfortunately I only used KDE for a few days, so there won’t be more oxygen-themed graphics from me. I liked its looks very much, but looks aren’t everything.