Both cameras are priced the same in the US, $2099.
A comparison of the important specs, taken from Canon/Nikon's web sites (Canon Rumors is wrong about the 6D having a 1/8000 sec max shutter speed, it is actually 1/4000 sec with 1/180 sec max flash sync).
I'm not going to voice any of my own opinions about this camera, though I will say I moved to a D700 for a reason. I just want to put all of the correct specs in one place so that objective comparison is simple. From comparing the specs, there is a pretty significant difference.
D600:
-24 MP Sony Sensor
-39 Point AF with 9 cross points (in a 3x3 grid in the center)
-Built in flash with wireless flash commander
-5.5 FPS
-1/4000 sec max shutter speed, 1/200 sec max flash sync
-Dual SD card slots
-100% viewfinder coverage, compatibility with DX lenses
-Optional wifi/GPS
6D:
-20MP sensor
-11 Point AF with 1 cross point (the center one)
-No built in flash
-4.5 FPS
-1/4000 sec max shutter speec, 1/180 sec max flash sync
-Single SD card slot
-97% viewfinder coverage, not compatible with EF-S lenses
-Built in Wifi/GPS
they are forcing many of the current 5DII users to upgrade to the much more expensive mkIII


