I’ve only been to Belize, Caye Caulker and Caye Ambergris, and loved it. Nice and laid back, not too expenisive, they take US money & speak English so it’s easy to get around, snorkling and parasailing are there. On Thursday nights at the Spin drift hotel in San Pedro you can go to the “World Famous Chicken Drop”! I stayed at that hotel, but missed the Chicken Drop. You can also stay at fancier hotel/resort places. I was only there for a weekend, but there are lots of other fun things to do that I didn’t have time for.
Also, if you go to the bar attached to the Spin Drift aks for the bartender Bling, he knows everyone on the island and can hook you up with good deals. (My aunt was in the Peace Corps there and he was her favorite bar tender.)