If you're using 5D2, I can't see you upgrading to 6D. However for a rebel user, a 6D is very appealing. WTH, some of these shots were taken with Nikon D200. For me, brand doesn't matter. Even your camera body doesn't matter that much. Lens does matter more than the camera body. But in the end, the one who takes matters most. Enough of gear whining.