The focusing is ok its the users. its only a tool learn how to use it to its
Briansquibb, is that you?
Let's be clear - the 5DII's AF isn't crap. It's decent if you know and work around its limitations, which is the same for any tool.
But your example really doesn't support the AF of the 5DII as being particularly good. It's a panning shot, and the camera-to-subject distance isn't changing appreciably as you pan. It's a great shot, like Brian's kart shots, but it would be pretty simple to manually focus and get a similar shot.
The OP is wondering about portraits and weddings. If he plants himself at the back of the aisle as the flower girl skips toward him, the 5DII's AI Servo AF will likely not be able to track her as she comes toward him with a wide aperture/shallow DoF. OTOH, a 7D (or a 1-series body) would have no trouble with that scenario.
I was out last night shooting with the 5DII in rainy/sleety conditions - shooting low light street scenes and there is now way my 400D would have been able to lock AF onto anything, whereas the 5DII performed excellently.
I certainly agree. Granted, the specifications are the same - what matters in that scenario is the EV rating of the AF system, and for the 400D,7D and 5DII, that rating is the same: -0.5 EV (by comparison, current 1-series are rated down to -1 EV and the 1D X drops another stop to -2 EV). But subjectively, my impression is that the center point of the 5DII outperforms the 7D's center point in very low light (and the 500D/T1i I had before, as well). When I attach a Speedlite, the 7D starts firing the AF assist lamp in light levels brighter than when the 5DII starts needing the help. But that's the center point only - in dim light, IMO the outer points of the 5DII go from being not-that-good to being nearly useless.