"I started out with Paint Shop Pro 7 and used it until I had come to such keen knowledge of it that I was clearly aware I had finally surpassed its capability and upgraded to PSP10."
I know what you mean. I used Paint Shop Pro 5 for years, switched to PSP7 and then eventually PSP9 which is what I'm still using. After using a piece of software for so long, you start to notice its flaws. The reason I kept using it for so long is because I'm comfortable with its UI.
I think I'll be comfortable with GIMP, even if there is a gap in quality from the best of graphics editing software. I was really just curious about it.
GIMP does seem to have a weird interface though, hehe.