I received a loaner 7D2 and 70-200 2.8 IS II late this afternoon. The pictures are amazingly sharp, sharper than I've seen on the body yet.
Unless: you put the AF into Servo and shoot a stationary object. I tried the same 3 shots, on a rock on my end table.
7DII: Single Shot: sharp, AI Focus: sharp, AI Servo: fuzzy
5D3: Single Shot: sharp, AI Focus: Sharp, AI Servo: sharp
The flaw is perhaps the "advanced" AF unit gets fooled if pointed at a stationary object in AI Servo? If someone else can try this out too and let us know the results, that'd be awesome.
This is interesting info.
There have been proponents of always selecting the "correct" AF mode going back to the 20D/1D2 era,.
I personally have always been of the "set it to backfocus button and leave it in AI Servo 95% of the time" with good results, but a new AF system could surely change that.