I'm very glad to see that many replied to my post!
I am also glad to let you know that I have this amplifier since Dec'04 and drive my B&W Nautilus 802.
I use a greek high-end preamp Tsakiridis Alexander and a Primare DVD30!
I can tell that the power of the amp is almost unlimited!
I let it on almost continously (Yamaha recommends), and the sound is wonderful
Nautilus 802, is a very difficult and "hungry" loudspeaker! but MX-D1 offers power more and more...
Well!
We here in Greece have a AVsite forum and performed many "blind" tests with this amp and many loudspeakers and other "monster-looking" mono-blocks!!
He was uncompetable!