The AF is great if it is well lit. You can get great action stopping pictures with the mark II. It doesn't do well is poor low light, but in good light, it does awesome.
Low light AF is amongst the best for the 5DII on the centre AF point
yep I shot an awesome performance in yangshuo in china with the 70-200 on a tripod with the 5Dmk2 and i would say focus is dead on in about 99% of the shots very very low light
super super happy with the results (still havent processed them yet but even the raws are great)
thing is i feel the 5Dmk3 can acquire foucs in even less light than the mk2 (very slowly though but it will lock where the mk2 wont