Can i ask what RAW processing software was used for each?
I was asking about this comparison a couple of weeks ago, did you get my e-mail i sent to you then?
Since then i have been able to try out the Mamiya ZD camera over a period of a few days against my 1DS3 and have so far come to the conclusion that although its files have a very nice look and feel, the colours are all over the place compared to the Canon, albeit sharper and slightly more detailed. However i did not have access to the Mamiya software and processed them both out in Lightroom. In terms of actual use, they are light years apart, the Mamiya being unbelievably slow and clunky in operation, but that's another story.
With the ZD use RD, I think it does a great job. LR or camera raw does a good job with better colour.