H - I saw a post of 2 different 5D mark iii images from different RAW converters and it did make quite a difference. In the example I saw it was mostly a difference in sharpness rather than noise or banding but certainly a good converter is a must.
Here is a DigitalRev review of the D800 which is informative:
http://www.youtube.com/watch?v=MT6il...alIrPkkN0gA%3D
The main problem with the D800 seems to be simply getting one. They are in super high demand and Nikon is struggling to meet the demand.
Hopefully it settles within a month or two.
Greg.