I don't know who they make amps for these days, but the founders of the company came from a company called SAE, which was some high quality gear (amps & pre-amps) back in the 70's and 80's.
ATI got great reviews from Home Theater Mag in the 90s, and I listened to some of their earlier, less powerful models. I listened to them through PSB Stratus Golds, Martin Logans, Maggies, and I tell you what, the ATI's handled every speaker without any problem. The models that I listened to were 1505, 2505, and the 1805, and they all had had some serious power, really good bass, tight and controlled. They rock for home theater, and they did two channel pretty darn good too.
So if you're looking at their 3000, I would only assume that it will be even better than their previous models. Hope this helps. Good luck.