Looking to compliment my 7D with a FF. I do mostly sports so the 5d MkIII would be a good back up for that. While I have never held a 6D I was considering it. Now that I've read this thread the Mk III is a front runner just for the reason of similarity's between the 7D and the 5D. Small but significant differences are the SD slot, WB adjustment, weather proof (I live in the PNW and shooting in the rain is a factor), button functions on top of camera (I can see myself getting frustrated during a shoot if I have to make adjustments on the fly). I earn money with my photography, and I feel that the less distractions during a shoot the better off in the long run. Photography isn't my first income, but an income non the less. Someone posted My Grandpa told me to "buy the best and cry once." I laughed, but how true. I believe that each of these cameras have a place. Each person that has posted here have different needs, so one camera is not better than the other, just a better fit. If I didn't earn money with my cameras and it was just a hobby as this started out to be, I'd go with the 6D. But as I depend on my equipment and familiarity plays a role, the Mk III is a front runner. Good luck, good thread.