Hey-
While I hvent heard the Marantz, I have heard the Rotel, and am planning on purchasing one. If price is a concern, and you are planning on running a 5.1 HT, you might also consider the Rotel 1056. I know that the 1056 is rated at 75 x 7 vs. the Marantz spec of 7 x 110, but I dont know how much I would trust the Marantz claim. Rotel is know to be fairly truthful about their power ratings, and occasionally underrate themselves.
A few bits of info:
Weight
1067: 54 lbs
1055: 38 lbs
8400: 35 lbs.
More power means more weight.
Power consumption:
1067:990 watts
1056: 450 watts
8400: ?? The applets on their website kept crashing my comp, but worth checking out.
And in the end, this isnt about numbers and stats....find a dealer who is willing to let you try them out...go with your ears, money be damned
Hope some of this helps.
Matt