I did the Pinel Island Excursion in St. Maarten with my husband and 4 yr old daughter. I was not that impressed. Although the beach was pretty, the snorkeling was a dissappointment. The bus ride wasted alot of time and then you got on this horrible little boat to get you to Pinel Island.
However, our excursion to St. John was awesome. We took the snorkeling excursion with the boat LEYLON. This boat is really nice, great ride over to St. John and then you snorkel at Trunk Bay. Would do that again, definitely recommended. You had the option of snorkeling in deep water or they brought you to the beach where you can either snorkel in the cove or just swim. The most beautiful beach I have ever seen is TRUNK BAY.