1) Are the raw files just soft, or terrible in other respects?
2) Is it the smearing of the details that makes the jpegs so bad?
I hope this is just an issue with the DPP software.
1) Raw files in DPP preview look sharpand show lots of detail, when i preview in bridge with ACR6.7 installed they are noticably softer and editing in DPP much softer, opening in PS also softer than the DPP preview. Colour all looks really good, The detail has to be in the file, as it displays in the DPP preview so i'm not too concerned about the senor being a lemon. I feel its almost entirely related to the processing software not being right rather than a sensor thing.
2) the jpegs look awefull IMO, like heavy handed NR is being applied to iso100 files. sure NR the hell out of 25600 iso images in camera but there should be 0 NR applied to iso 100 jpgs. If i took a 5D2 raw file at iso 100 in topaz denoise and applied an overall noise reduction value of maybe 60 this would be similar to the jpegs out of camera, my typical use of denoise values are around 20-30 if i'm correcting 1600 iso to 3200 iso, i may sometimes pop a value of 5 on a portrait as it does a nice job cleaning up skin in a very subtle way that is not noticable as being post processed. (these are observations based on the standard settings the camera comes with, I dont work with jpegs at all other than to flick to people for a quick preview and usually i will downsize those to 1024x768 anyway if i'm going to email them. On my 5Dmk2 i record medium jpegs which are 10MP for this purpose on my 1Dmk3 i leave the jpegs full size which is also 10 or 11 MP.
Overall I'm very glad I didnt sell my 5D2s just in case, I really hope these issues get resolved soon as I'm going to china soon and really wanted to put this thing through its paces. At least i know i can rely on the 5Dmk2s anyway. I wont be shooting any paid work with the 5Dmk3 untill i'm 100% happy it can meet the 5Dmk2 standard though.