We joined in on the excursion last week. We have been on several catamaran excursions throughout the Caribbean, and we were very impressed with the personalized service. Each passenger was made to feel that this was THEIR own private excursion.
We had considered going on the excursion again, but we are comfortable snorkelling on our own, so have decided against it, but not because we didn't enjoy it! We purchased the DVD from the photographer on board. Other than the short preview, we are not sure how good it is since we don't have a DVD player in our room. He was sure sneaky, though-going very deep, with just fins. I would recommend this excursion, particularly for those wanting help in spotting the sea-life.