Maybe, if you have never snorkeled before, you may like this. However, for $89 each, on a FULL cat (group of 70), it was very disappointing. We did this same cruise in 2009, and have also stayed a week at Provo in 2010, just stayed a week at Belize last Oct., so we are experienced snorkelers.
Good points: the crew was excellent, very nice, and very safety oriented. Although no one said it was their first time snorkeling, we all got the safety speech which is totally fine. I would question any outfit that didn't do this. Drinks flowed freely, they were as strong as you wanted. Ship was in "good" shape.
Not so good: At the wall for our snorkel. We saw maybe 3 species of fish. We were in very deep water, excellent for scuba, not so good for snorkel. When ever you get such a huge group (another full cat of 70 also pulled up next to us from the Ruby) all you do is bump into people. The crew had their hands full, so we could only snorkel in a very, very small spot. This was disappointing as I know how good the snorkeling is in this area of the Caribbean.
I think that the folks snorkeling at the outer edges of the Margaretaville area probably had just as good snorkeling. It's too bad that this was so expensive for lousy snorkeling.
I heard some folks say this was an excellent excursion, so this is just my opinion. Snorkeling is probably my family's most favorite thing to do and we go all over the Caribbean, Kauai, and the Big Island.
Be warned. Perhaps you can find an independent, smaller company that can spend the time and provide a quality snorkel experience instead of a boat ride with booze.