Upload & Sell: Off
I have used the 70-200 f/2.8L IS II with a Canon 2x II on my 7D, and while I the found the image quality to be decent (in some aspects nearly as good at 400mm as the 100-400, at least for a cropper - not sure about full-frame), I felt that the servo focusing was not great and I was better off using my 100-400 for focus reasons.
With the 5DIII's better AF system, I am wondering how the 70-200 II and 2x II (or other 2x T.C. that you may have) does for servo AF performance. Still sub-par, or something you can rely on?