This was the first time I tried surfing shots -- it was a lot of fun and in a lot of ways much more predictable (aka easier) than when I tried shooting kite and wind surfers. You pretty much know where the surfer will be (after all the speed and direction of the wave are pretty linear), and you only need to worry about turns within that plane.
It really helps if you practice the sport to know when the crucial moments are. Watching it can do the same thing but it takes longer, IMO. I got into kitesurfing a few years back but I haven't gotten into shooting it much--it's just way more fun to be doing it. I'd love to get a UW housing for that and surfing, though.