We went there & it was awesome! I would suggest staying the whole day there instead of a split stay with visiting the ruins, but we like to swim and relax not do tours so this was right up our alley!
They do have a meal plan, which we did not do. The coolest thing for us was the garden where all the tropical birds hang out. They will fly right up on your shoulders for any kind of food! We brought some rolls from our hotel to feed the fish and ended up giving some to the awesome birds, even wild toucans! I would suggest bringing some rolls so you can feed the fish when you snorkel, it will be amazing!
There are tubes to laze around in, and they even have a lazy river, all natural of course. If we ever go back to this area this park is a must do! they do have a dolphin swim which I did not do. It was expensive if I can remember...