I just got back from a trip to the Caymans and I did the Stingray City dive with Red Sail. I would recommend doing the dive as there is sooo many people snorkeling at the sandbar. We were nearby one morning inbetween dives on the north wall and there must have been at least a dozen boats, some packed with people from the cruise ships. Red Sail goes out in the afternoon, and when I was at the dive site, there was only one other boat. Being underwater, you experience the stingray's swimming around you. My wife and two friends came on the dive boat to snorkel the dive site which I would recommend over the sandbar if you only snorkel. Much less crowded and less touristy. Our dive master brought up one of the sting rays to the snorklers. I would recommend Red Sail.