I've owned 4 different U.S. amps (3 sub amp (2-channel) and 1 (4 channel) they have all been underrated and had great sound quality. Very stable too. The first one I had was old school and I was running it at 1 ohm with the gains pretty much maxed (yeah, I was totally a newb). It got HOT but never once shut down. Great amps. Flakko can get you a really good deal and he gets the stuff to you fast. I bought a 4 channel from him about 8 months ago.
You could try an older style one too. I see them on
ebay all the time. They go for good prices. Try different variations of the name thats how I find good deals.
USAMPS
U.S. Amps
U.S.amps
etc