The beach is average. It's not a beach like say east-cost Florida. Beach is not wide/deep like that. It's attractive, palm trees and the like, and the facilities are pretty good. We were not disappointed.
FOrget the ships excursions!!! Save yourself more than 1/2 that cost (and see more of the island too) by simply getting off the boat and hiring one of the waiting locals for the day. On your way back have him take you around the island, On the back side is a small village with cheap shopping.