For the past year, since buying my 7D, I thought it or the future 7DII would have a permanent place in my kit. Now, I'm not so sure.
I'm a two-body shooter. The 7D is now my second body, but I find myself shuffling lenses to shoot mostly with the 5D3, thus defeating the purpose of using two bodies. Need to payoff the 5D3 first, but I'm already considering a second FF down the road and will be weighing the merits (and price) of the 6D vs. another 5D3 for this purpose.
Curious side note. The full resolution JPEGs from the 5D3 volleyball shoot averaged between 5-6 MB. Those from the 7D averaged 8-9 MB. ISO for both cameras were mostly 3200. I'm guessing that extra noise accounts for the added data in the 7D files.
Also, I made a rookie mistake during the first game. In switching from RAW to JPEG, I inaverdently switched to Large compressed. But, even those images are cleaner than the ones from the 7D.
Funny that TrumpetPower mentions the 135 and 645 comparison. Decades ago I went from a Canon FTb-n to a Mamiya 645 1000s. When I first started playing with the 5D3 around the house and comparing it to the 7D, I did think "this is a lot like the Mamiya" -- only a tad lighter.