I've seen QSC amps recommended for sub applications several times over the past severa weeks, and have browsed their site and some on-line retailers several times to get a feel for power/price/specs/etc. Today I wanted to get a better idea of just where they stack up to the competition. After spending quite a while reading on QSC's site, I'm left a bit overwhelmed and confused. Primarily, I haven't quite figured out what the major differences in their large array of lines are. Specs look very similar in many different lines, and power output overlaps in dozens of places it seems. I'm kinda scratching my head, thinking "so which ones are the 'good' ones?" I see that most of their lines have a "70 volt" model(s). I'm assuming I don't need that, but what exactly is that for, and why don't I want those models? QSC doesn't really delineate what their quality lineup is from top to bottom (not that I could really see). Could someone give me a hand in sorting this out?