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Sounds really promising. I know Canon did not design the 6D for use on BIF, sports or airshows, but if its faster and more responsive than the 5DII, then it would be fine for me.
The 6D AF performance has turned out to be a big deal for me, so I'll offer up some detail.
I find that shutter lag is improved to the point where it is a non-factor: on a par, I'd say with the 7D. I've already posted re BIF, but where I'm seeing a big improvement is with AI servo on things like ducks & grebes just swimming around. When their movements are more or less random, & they often are, I've previously had trouble really nailing focus. Not talking about almost on, but dead on. Recently in just such a situation I was delighted to discover that the 6D performed better than any camera I've ever owned, including several 1-series bodies. For slowly but erratically moving subjects the 6D is dynamite! Focus acquisition is not all that fast, at least with a 100-400, but accuracy is just outstanding, shot after shot. Note: using center AF point only.