I've been using GIMP recently since the 2.1.0 and its outstanding compared to what it was before with the white background and horrible "floating" toolbars.
The new version really is a revelation, and the developers should be congratulated for their efforts. The startup time had been annoying so I am glad to try out this latest improvement.
The only thing I would change is having plugins based in a simple standard python language, and better online videos on their youtube channel to teach new users. Oh I would also make the colour icons default just to make it look nice out of the box ;)