Sorry I didn't get a chance to take any photos last night. I've got my 6d on me today so I've taken a few more. These look pretty noisy because I didn't shoot to the right, I just let the camera's evaluative meter decide the correct exposure. Pretty sure if I'd have changed the exposure by a stop then a lot of the noise would have gone. In my limited use of the camera I've found it tends to underexpose slightly at times.
The only thing I've done is added some noise reduction in Lightroom 4.4 to the photos (the luminance slider is set to 40 in each case).
The first is from sRaw mode:
Next up is mRaw mode:
And finally normal Raw mode:
For me, there seems only 2 choices - shoot in full Raw mode if you wish to retain maximum resolution or shoot in sRaw if you need to save on space (the files were 13, 19 and 26mb respectively). The sRaw files are clean and sharp whereas I found the mRaw files to look a bit muddy.
I'm annoyed I didn't get a chance to compare with the 5Dc so tonight I'll do another test, this time exposing to the right on each camera, and I'll also throw the 550D into the mix. I've lent my 400D to someone otherwise I'd include that to see how technology has moved on over the years.