Upload & Sell: On
I bought my 5D3 to replace my 5d2, because of the better AF and higher frame rate. I had been using the 5d2 for "general" photography and the 7D for sports/wildlife.
The benefit to me has been that, when I'm not going to be focal-length limited, I can now use the 5d3 for birds; my favorite bird photos with the new camera were entirely accidental, when I surprised a huge vulture and a large bald eagle as they munched on a dead deer mere yards away from me. With the 5D3, wearing a 70-200, I was able to get a number of wonderful, detailed shots of the two birds as they flew away. I don't know that I could have obtained the same results with the 7D, with its smaller FOV, and the IQ of the 5D3 pleases me more.
Otherwise, the tangible benefit has been that, when I want to travel a bit lighter, I'm still fully-able to take photos of small moving things carrying only the one body; previously, I was severely limited in the keeper-rate with the 5d2 (not zero, but not in the same ballpark as with the 5d3).