The obvious thing is matching your speakers with the right amp. I would expect both the MA7000 and the Continuum 500 to be excellent units, I'd love to experiement myself.
I have owned two Concentra II's. The first I had I loved and always regretted selling, it was a great match wth the speakers I had. But I replaced the speakers and after doing so I wasn't so pleased, so I played with amps. (It was the speakers, I eventually sold them.)
I later purchased another CII in hopes of selling my spearates, as I had spent a lot on speakers and wanted to even the finances out. My separates were (and are) McIntosh MC402 and C46 and the CII was no match, at least with the speakers I was using.
Above Jimmy mentions the MA6900, which IMO is not on par with the newer MA6600 and MA7000. A friend recently purchased a MA6600 and is extremly pleased with it, replacing Bel Canto mono blocks and pre.
Again, speaker matching is important, but if you have to lean on opinions, Jprice would have to be one of your best sources as he has owned both. After reading his comments, I'd love it if he could have a Continuum placed back in his system, after some more time with the MA7000, and get further thoughts; I am surprised by the lack of 3d with the Mac, a usual strong point for them.