the 5D smokes the D600 in everything except DR where the Nikon wins. Huh? That video does not show 5D "smokes" D600. For IQ, I would say they are about even with D600 having a bit better DR and 5D III a bit better high ISO performance. $3500 vs. $2200 gets you more pro-like functionality, but for the hobbyist, the D600 produces impressive IQ. Since I already have the 5D III, I can only hope the 6D can compete with D600 when it comes out..
I am not holding out much hope for the 6D. I think they went more consumerish with the body, design, and specs than Nikon did with the D600. I was really hoping for the 7D with a FF sensor & digic V chip and thought they could do that for under $2200. Nothing else needed to be changed. The size, build, ergonomics, speed, focusing, and resolution of the 7D are perfect and I don't need wifi & GPS built in. The 6D is really more of a FF 60D and the D600 more of a FF D7000 and the D7000 is more of a hobbyist/prosumer camera than the 60D. I'm loving my 5DmkIII but i'd really love a smaller/cheaper backup/family vacation camera that can still hold its own in a professional shoot like a wedding. I'm torn between keeping my 7D (love but not FF), getting a 5DmkII (slow & crap AF), or another 5DmkIII (large and expensive for a 2nd body).