Originally posted by Mike Cash The point was not that the AF yielded twice as many out of focus shots.
Actually those figures lie well within a margin of error (scientifically speaking) and I think it would be more appropriate to say that, for you, there is no practical difference in the number of keepers. However, I'm assuming you were sitting far enough away from the dancers that your DOF was pretty large and focusing would be easier than in other fast-moving situations.
They both have their place, and it's not easy for a budding photographer to get as good at manual focusing as one of these super-fast AF systems with short focus throws. However, in other situations it might make no difference, so it would be best to select the lens with the proper specs and IQ, regardless of focusing.
In sum, I really think it's best to have both - and be prepared to spend a long time taking crappy pictures if you are new to manual focusing because it is not nearly as easy for a newbie as it is for a lot of veterans!
IMHO though, manual focusing is more fun. I was never into guns (firing ranges, skeet shooting etc) but I get that sort of "thrill" when a fleeting moment passes and you have to aim, focus, and fire before the moment is gone.