Afraid I have no usefull camera based info as I only have a lowly 7D and have never knowingly seen either a 5DIII or 6D in action.
How about you all agree to disagree on this point, I have seen what started as a valid positive post degenerate in to a mud slinging session. I value comments from all on this forum, everyone has something to offer that may help me improve my technique and get more from my hobby, everyone also has their own opinion and these are as different as can be, wouldn't the world be boring if we were all the same!
Tis the season to be jolly, of goodwill to all men etc etc.
So please no more mud slinging. Let's get back to normal service of getting along and improving our hobby.
Thank you for the positive sentiments, and Merry Christmas to you!
For what it's worth, even I admit the 7D can autofocus better than the 6D in good light! Far better actually. I am not here claiming the 6D can autofocus better in good light than any camera, actually. Maybe it's better than an older Rebel, I don't know. For some lenses the 6D AF's better than my 50D did, for others it does not. The 50D was not terrible at autofocusing, it was pretty good.
I'm just against the thought that the 6D can't ever get more than half its shots in focus while in servo mode, because that's definitely not how it is. Anyone who says otherwise is either using a 6D with a faulty AF sensor, or they're intentionally tripping it up by relying on the outer points (as in by using all the points...because again, the little man inside the camera that tells which points are dominant, is keen to let those lesser capable outer points have sway over the better center point, especially while in servo mode.)
This is not a difficult phenomenon to observe...the points light up. Who are you going to believe, me or your lying forum eyes as they read the naysayers?
...So for the millionth time...don't rely on 6D outer AF points in servo mode. Use the camera correctly, or else don't complain.
If you simply must have all points active, or you want a large or spaced group of precise points and a fast, high performance autofocus...pay the extra money and get a different camera. But don't tell me I don't get over half my shots in sharp focus, when I do...