We just came back on Friday and did experience some of the wind you've heard about. It wasn't as bad as everyone made it out to be. On the really hot, sunny days you'll appreciate the breeze! As far as snorkeling goes, we did postphone our trip one day (since we had a whole week of chances ahead of us). We did go on a kind of breezy day to Hol Chan & Shark Ray Alley -- the visibility was perfect, no problems with currents or views. One recommendation is don't wait till the end of your trip to go on a snorkeling excursion. It was so amazing, but we waited till the end. If I would have known how much fun we'd have we would have gone two-to-three more times!
HAVE FUN!