IMO- The Flower Gardens are great. Cost runs around $450-650 per trip depending on time of year and length. Opportunities to see Whale Shark, Hammerheads, Silky and occasional Bulls. Manta Rays are common as well as are tons of Barracuda and Jacks. As always plenty of the common reef fish and healthy corals.
I would suggest an advanced certification a least or experience with the conditions you would expect diving in open sea.
Cozumel is always great dive destination, but the Gardens are an awesome experience just don't expect to be pampered. If you are looking for easy-laid back diving stick to the resorts............
