I guess it depends what you are looking for. I personally enjoyed Captain Bryans because its a Catamaran trip, you sail to the sandbar to swim with the stingrays rather than a diesel motor boat. There is a really nice photo of the Hannibal, Captain Bryans Catamaran here Captain Bryans Hannibal Catamaran
We had a wonderful trip, only about 16 people and the catamaran is a 50ft! Loads of room, you can lay out and tan or if you want to be in the shade there is a nice covered area. Stingrays are really amazing. It was a wonderful trip!