I've had very good experience as well with customer service and product as well. Just purchased an AT 1200.1 d amplifier. It arrived yesterday, I need to hook it up soon to my 2 dayton ho 10s so I can see how it sounds. I'll let you all know, I know noone knows much about their amps yet. I hope it sounds good, amps are always a big mystery to me, seems like nothing is rated or manufactured or whatever properly, seems to always be a crap in shoot for an amp, unless you spend a lot of money.
Looking at the AT 1200.1 d guts, there are some inperfections, the capacitors, resistors and some of the components on the board are cockeyed. Technically they are connected so it shouldn't matter. But to me it says a little bit about the build quality if all the things attached to the board aren't slanted or crooked, but instead straight up and down.
What remains to be seen though like i've said is how it will perform. The price is sure amazing if it can do the power well. Clamped at 1700watts apparently, but the only tests I even consider are ones with actual loads on the amp.