The ATI AT2000 is a balanced bridged amplifier. The M7 looks similar to the Outlaw 7200. If I recall correctly, the 7900 had 24 lower Safe Operating Area transistors per channel where the AT3000 has 16 higher SOA transistors. My guess is that, at the time, Outlaw was in a spec war with Emotiva.
I don't know if that has any meaningful difference. Personally, if the price is similar, I would go ATI.
- Rich