We did the snorkelling tour for 53 dollars (pre-booked in our bus company). It's basicaly 1 hour sailing to reach the coral reef, 1 hour in the water and 1 hour back (drinks are included).
The visibility was not so good and, in my opinion, not worth the money.
They told us that up to 100 persons fit in the boat. As you can imagine, so many people swimming can scare the nature in the surroundings.
The staff is very friendly and, if the weather is good, the view is so enjoyable sitting on top of the catamaran.
Up to you to decide the activity...
This company was okay for snorkelling, we saw one dolphin in our way and some fishes in the snorkeling spot.
Not sure what else to add.