It is hard enough for me to convince people that GIMP is quite capable of doing pretty much everything the average user of Photoshop would require from it without you guys up and moving shit around all the time, and/or releasing "stable" versions that don't function properly. Had I not had 10 years of wonderful experience working with GIMP before running the version that Ubuntu installed for me, I would have not only been pulling my hair out, but I'd be advocating that no one ever waste their time with it in the first place as well. Stuff just doesn't work. Weirdnesses to which I had finally adjusted are now either gone or weirder. My active layer keeps getting into a state where neither I nor plugins can change it. Selections are behaving strangely. I'd hate to have my income be dependent upon using GIMP, because I'm having serious troubles getting anything done with it right now.
Granted, Ubuntu is giving me a somewhat outdated version, but I would think that however old the version is, coming from the "stable" tree would ensure that it, you know, would WORK properly? I suppose it's possible that the Ubuntu folk may have broken something after you were through with it, but I can't help but wonder whether most of the Internet ravings from Photoshop users about how GIMP is worse than MS Paint might be as a result of crap like I'm running across now. I know that GIMP is a top-notch application that, aside from some annoying quirks from time to time, is perfectly capable of replacing what 95% of Photoshop users use it for (despite that not being the intent of GIMP in the first place), but trying to get anything done with this release (2.4.2) is proving impossible for this 10-year veteran self-proclaimed GIMP 'expert.' I'm pulling my hair out trying to get anything done; I'd suspect new users, however, would just tell their friends how much it sucks and be done with it.
In the decade or so that I've been using GIMP I've gone from the bleeding-edge compile-it-myself-the-minute-it's-released type of user to kind that just uses whichever release his package manager presents him with; I'm pretty sure the latter is the group that most of your user-base falls into. You need to make sure that those people don't come across crap like this, because they're the ones who aren't going to put up with it and end up saying bad things about you. Isn't that why you have the unstable tree in the first place?