I've never tried GIMP, but I'm sure it's not really that much more complicated.
Well, I use GIMP all the time. And I agree that it's complicated. Or more accurately, it has a fairly step learning curve due to some UI issues (IMO). I think most people can figure out what layers are supposed to do in a paint program, but with GIMP if there's a selection on a particular layer and you switch to the Pencil tool and try to draw on the image it may not work. The problem could be: the layer is locked, you're drawing outside the selection, the opacity is set to 0%, and a couple other reasons. If you're familiar with GIMP you'l know what to look for, but I've been using it sporadically since the days of v0.9 (back in the early to mid-90's) and I still
get screwed up by such things.
If I used it more regularly it probably wouldn't be an issue...