Coming from two Canon 5d MK II bodies and killing one, which I replaced with a mk III. I'm seriously considering selling my mk II and getting a 6D as a second (walkaround) body. The low light AF (dis)abilities of the mk II really bothered me since its release and reports of the 6D are very positive in this regard. I also have the cash for a second MK III but at this point I find it a little overkill to use a 3K camera as a walkaround body dangling over my shoulder or wrist wherever I go, but the 5D Mk III is a JOY to use and love the images I take with it. It is a fantastic camera and the images looks more "natural" to my eyes than the the 5d mk II ever did. And reports that the IQ of the 6D is at least as good as the 5d mk III gives me a reason to ditch the 5d II for one of these two bodies. I can't choose!!
I replaced the 6D for the 7D in my kit to go along as a second body with my 5D3. It makes a great combo with teles on the 5D3 and WAs on the 6D
1DX, 5D3, 600D, RX100
16-35L, 24-70L II, 70-200L II, 100-400L II, 50L, 85L II, 135L, 17TSE, 24TSE, 40, 100 macro, 18-55 II, 55-250 II, 1.4x III, 2x III, 600RT x 4
When it comes to gear, it is better to vote with your wallet. Bitching on online forums like a lunatic doesn't get you anywhere!