i havent had the chance to play with a 5dmk2 yet...so before i take the plunge, im trying to figure out just how 'bad' the focusing speed is on it, cause i have the chance to pick one up at a fantastic price. i shoot primarily motorsports, but im starting to get into studio stuff a bit more these days, but since my main focus is still motorsports, will the 5dmk2 focus not be able to keep up with it? right now i have a 10d and a 30d. will the focus on the 5dmk2 be atleast as good as the 30d? cause having used the 5d, i found it a bit worse than the 30d in terms of speed and locking accuracy. or would i just be better off looking to buy a 1dmk2 and a 1dsmk2?