I used to do miniature painting at Gencon a million years ago, and have had a handful of friends who regularly work the art tables at both Gencon and Dragoncon. I've heard plenty of complaints but honestly, nine times out of ten, the person doing the complaining is usually whining about something that's their own fault.
I can't imagine that you wouldn't find it a worthwhile experience. You're far too talented to be overlooked, regardless of how crappy a booth you get stuck in.
Depending on what you're looking for, and how much space you want, I might be able to hook you into a couple of people who like to double up and share booth space with each other.