Thanks for answering... do you have any apples to apples axamples?
Not really. I expected the sensor to be equivalent to the 5DII at most low ISO's, and better at higher ISO's. But if you go look at the comparisons at DPReview, the 5DIII looks equivalent, and maybe even softer even at ISO 100. And they used the RAW files and did an ACR conversioin...
So I took my 5DII and 5DIII into my studio, and shot some teddy bears at ISO 100. No need for tripod since strobes are used, but the framing wasn't exactly the same. Regardless, both showed great detail, the 5DIII looked a bit sharper actually, but that might have been the focus. It was more accurate at autofocuing on the teddy bear nose than my 5DII.
I also did some ISO 1600 or ISO3200 tests ( can't remember ) and both had plenty of noise, but the 5DIII images just looked better for some reason, more DR maybe, or better colors.I had a hard time pinpointing it, but my wife agreed.
Also, my wife and I just shot an engagement session together, she used the 5DII with 85 f/1.2LII and I used 5DIII with 70-200 f/2.8LII. She is processing the images and mentioned that the 5DIII images look better, but not dramatically or anything. That was an ISO100-400 shoot.
Anyway, I'm personally waiting for Canon to fix DPP so that we can see a review at www.the-digital-picture.com
to see a more controlled test with proper processing.