Just received my 6D and I'm playing around with it and the bugma ! so far it's a huge improvment compared to my old 450D This has been shot at 12 800 ISO and there is less noise than with the 450D at 400 ISO... Even my bugma can't believe its eyes.
I think I'm going to love it.
Test picture to see how the 6D manages high ISO, straight from the camera. There certainly is noise but far less than I expected.