I've had two Carver ZR1600's running for about 30+ hrs now and they seemed to have leveled out as far as break-in goes. These are incredible amps for the money, but I don't think they are 'giant killers' as I've heard them referred to. I can imagine that someone with a difficult speaker load and a tight budget would benefit greatly from these amps, however, in stock form they are not SOTA sonically, at least not in my system.
I've posted a bit more information on this thread here
Amps for Magnepan 3.6r since it seemed to be a more appropriate venue.
I'll get another 40 hrs on them and probably do a review.