Booked beach and monkey zoo with Carlos at Islander Tours. He is so accommodating. Will arrange whatever you want to do. Even if all you do is the beach it is still the best, most reliable and cheapest way to go.
Went to Chankanaab because some had booked dolphin swim. Unfortunately it was cloudy and windy. They still loved the dolphin swim but it wasn't the best beach day. Because the dolphin swim was so long, we didn't have a lot of time to shop and felt very rushed. Don't know if we would go to Chankanaab again.