I've been using my #3 in USPSA. I have shoulder problems and can't draw from a straight drop holster very well anymore. I figured I'd get by with the #3 until I could get something made that rides lower, but I'm still right behind the GMs and Ms that have been beating me for the last ten years, so I think I'll stick with the #3. Makes leaving the match a lot easier. Just load up with carry ammo, put on a cover shirt and leave.
I think it's fun to give the big boys a run for their money in Limited Minor with an IWB holster and a stock Glock 19