All I can tell you is that I've just finished replacing the two EQs I was using on a lot of the channels on the project I'm working on w/ Q-10 and I'm delighted.
Speeds up my workflow quite a bit to be able to double the high pass filter if needed, use a couple of bands for surgical EQ to kill a couple of frequencies and then proceed w/ regular eq'ing duties, using only one plug-in. Heck, I still had a couple of bands available on the most heavily processed tracks.
My wish list is getting shorter though, w/ all the recent deals. Q-10 was on top of that list. That leaves (Waves) Bass Rider and maybe C4, and then McDSP's limiter, which I really dig but need to upgrade in order to use it outside of Pro Tools.