Well, lessee … Based on the random cameras on the front page of the site, the three year old Canon 5D is only a small percentage behind the Nikon D3, as far as RAW IQ is concerned. Since the D700 uses basically the same sensor and processing as the D3, and based on what I've seen from the pre-production samples, the RAW IQ of the Canon 5DMkII is going to blow the D3 and D700 right out of the water.
I also ran a few checks on their system, and have found at least one issue — I'm left wondering how a camera that processes RAW data at 12-bits can have better color depth than one that processes RAW data a 14-bits. The math doesn't hold true. Of course, DxO are the folks who worked behind the scenes on Nikon's RAW processing software, so I could guess they might be a little biased — more Nikon units sold=more DxO software sold? Hmmm…
That said … I think that the images from the original 5D, the D3, the D700 and even the Canon 1DsMkII have a better subjective image quality than the Canon 5DMkII and the 1DsMkIII. I think we've reached a point where things might be too good.