In the Caymans, we did Stingray City Snorkeling (G09) and it was amazing. Deep water snorkeling (10+ feet) at the reef edge with between 5-10 full sized stingrays at any given time. Incredible snorkeling adventure. This December we're doing Shipwreck and Reef Snorkeling (G15) which looks to be just as amazing. In Cozumel, we went on the cultural trek and went to Tulum (CZ06). The ride each way was long, but the tour guide filled it up with a mini-lesson about the Yucatan and the Mayan culture. The site was incredible. Our kids were 12, 10 & 10 when we did these. I had to go get the twins out of the water on the stingray city snorkeling.
In Jamaica we had a let down. We did Chukka Taste of Jamaica at Good Hope Estate (FA28) and it was disappointing. The big house - wasn't, the plantation was run down, the docents at the house had a cursory knowledge of the area and the site and the lunch was late and bland. Yeah, not impressed. Take it for what it's worth.