I don't have a 7D. But what I've heard and read from those who have both it and a 5DIII, even using the same lenses for little birdies when they're distance-limited with both bodies, the 5DIII still beats the 7D.
What you have heard and read is absolutely correct. The 5D3 puts the 7D to shame ... 1.6 crop factor notwithstanding!
Same lens, same distance, decent light, and a large print - the 7D print will be better.
That would be a fair assessment if the AF demands were not too stringent.
Nice shot ... but the point I'm trying to make is that the AF of the 5D3 is way much better than the 7D and will result in more keepers.
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!