I use it on commercial work sometimes, and I would agree that gimp is usability hell, but functionally very useful for a number of things.

I keep meaning to go and have a look at the source to see how easy it would be to reskin, because it could be a nice cross platform starting point for anyone wanting to make a really nice image editor, that doesn't ape photoshop, but goes for the less technical users while still having a mass of good functionality. Y'know, for the kids ;)