I wasn't able to complete the snorkeling excursion but my husband did and he did enjoy it. I think I needed a bit more time to learn how to use the mask and snorkel on shore before going right into the water with it but others seemed to handle it OK so I would actually give it almost a 5 and you do get to see lots of fish. My husband enjoyed it so much that he did book a 2nd. snorkeling excursion on Costa Maya.
Our excursion was cut short after about 20 minutes due to pouring rain but I am rating it 5 b/c had the weather been good I feel that the excursion into Carambola Gardens would have been just what I expected. If you are looking for a natural and primitive garden then give this a shot. The few feet I was able to see before it was cancelled had more of a wild jungle-like setting. Be forewarned, the trails are rocky, narrow and winding and not for anyone who is physically challenged. The garden tour at the western end of the island might be more appropriate.