Same as the D600, both are a bit odd really, probably lovely cameras but when you the prices settle down how much different is it to the next model up. The D600 is £1725 according to camerapricebuster but the D800 is only £2124 which isn't that much more really.
The 6D is just listed at £1799 so far, the 5dIII is £2469, bit of a jump but not too far if your willing to spend £1800 on a camera then £2500 doesn't seem that much further away.
http://camerapricebuster.com/Canon_EOS_6D_Body_pc.html