Today I got to listen to the MAC6700 receiver with the new Wilson Alexia speakers and Nordost speaker cables. I am told that, in terms of amplification, the MAC6700 should be much the same as the new MA8900 integrated amp.
I will say, the amp is dead quiet. I would describe the sound as powerful and clear, with decent sound stage and decent highs, but I am not sure the Wilson tweeter is the best match for the McIntosh amp. It seemed that on some crescendos the highs got a bit "shouty"and harsh. Vocals were smooth and precise. Bass was decent but didn't seem to reach that deep to me. Overall, the sound was impressive but I can't say it seemed that musical to me.
I realize that the sound today of course was affected and possibly limited by the room, which did not seem to be treated much. I do think I would like to hear the 8900 some time with different speakers.