We stayed at Banyan Bay March 7-14! It is great! One of the couples with us stayed at Caribe Island, and of the two you mentioned, I would recommend Banyan Bay. The pool at Banyan Bay is really fantastic!
The beach at Banyan Bay is one of the best that we encountered. They clean the sea grass each day and have nice lounge chairs with pads. We would stroll down the beach to Victoria House (very nice also) and back every morning and loved it. But, quite honestly, there is no snorkeling off the beach. We were really glad to have the pool at Banyan Bay after a morning of diving! Just my opinion, for what it's worth, just being on AC is a treat no matter where you stay!!
Have a great time!! Pamela