I don't know if this will help, we didn't take an excursion, but we took a taxi to Nelsons Dockyard and then went to the Sandals Resort beach and at the end of the beach there was a resturaunt in that served great lobster with tequila lime butter. I have wanted to go back, just haven't had the opportunity. The sand in Antigua is that beautiful white powder and the ocean is so clear and pretty. If you snorkel or dive I would think this is a good place to do so the visibility is really good. I think there are several reefs and dive spots near this island.
before you book a snorkeling or scuba excursion I would definitely do some research. We stayed at an all-inclusive and the water was really cloudy. My husband dropped his sunglasses in the water and he couldn't see them even before they reached the bottom. We did a snorkeling excursion through the resort and we were disappointed because we have had much better experiences other places. I would definitely stick to an excursion that people recommend.