You get what you pay for, and I know some ppl will have everything in the world to say about it; but Audiopipe is cheap for a reason (obviously, when you try to pay $100 for 1500wrms, you're not getting great quality). It's not the most well built, inefficient, and I have yet to see a test about it "doing rated" that mentions THD (distortion). I'm sure a few people would say the Hifonics Brutus amps are better than Audiopipe, and I even hated my Brutus so I'll never buy Audiopipe...Some ppl seem to like em though, and seem to get good results....guess it depends on what you expect from your equipment and how picky you are (I'm very picky lol). A local just picked up an APSM 1500 and says he loves it for what he paid.....more power to him....I still wouldn't touch one with a 30ft. pole after having better amps and seeing the deals u can get on good amps if you're patient....
Cliffs: They're cheap crap in my eyes. If you choose to buy one, its on you. Just know...ya get what ya pay for....