You'll be better of with a 6D. Just wait a little bit and it'll go down to around 1700 to 1800 just like the 5D3 price going down.
I'm very much happy with my 5DII I just recently got an amazing deal for, it was "used" but only about 3K clicks, even once the 6D comes down in price, like to 1700 (not a chance, gotta wait at least a year for that to happen!). The extra ISO performance and the AF that works better is great and all but not $1000 better (for me), especially with that grip, the 5Ds have that comfortable well fitting grip, the 6D feels like a rebel and won't stay in my hand for long with a 70-200. And no joystick... and that not-as-fast flash sync... should have added that swivel screen even if it meant more work for the weather sealing and weight