I purchased a 6D last week and got it in on Friday. I primarily photograph weddings and plan to use this alongside my 5DMII for personal and business use.
I have always wanted a second full frame camera to use when shooting weddings without borrowing my father's camera as a backup. As my 5DMII is at 164,xxx for the shutter count, I thought it would be best to get another reliable camera to have while shooting weddings. All I read, it seemed that I would be happy with the 6D when I have been used to my 5DMII.
I did some tests right when I got it on Friday and it seems good - the AWB seems to be a tad different, but that's all. My wife and I are expecting our first baby and we had a baby shower today. 4 months ago, my brother had a baby shower at the same location, so I was comparing the photos that I took today from the ones previously taken at the same location, but with my 5DMII. Post work is similar on both - very slight.
5DMII: 1/125 f/4.0 ISO 1600 80mm (24-105L)
6D: 1/100 f/4.0 ISO 2500 70mm (24-105L)
It just seems to me that the image quality is not quite the same and the color is less vibrant on the 6D. At this point, I am leaning towards returning the 6D and buying a used 5dMII for $500 less. Has anyone experienced this?