We had a great time on the Mayan Riviera. Stayed at the Grand Palladium south of Playa Del Carmen but the time we spent off the resort is what made the vacation. Its very easy to travel along the coast in either the collectivos or buses, both are dirt cheap. As was mentioned, there are spectacular beaches near Tulum. If you enjoy snorkeling I would recommend Xel-Ha. It is a huge lagoon where you can be in the water all day and see large numbers of big fish. There were parrot fish probably 3 ft long, had no idea they got that large.
I agree with others - I love Jamaica and look forward to returning, next trip will be east of Mobay though, need to check out the Port Antonio and Boston Beach area. But I want to see other places too, the world is too big to limit trips to the same place all the time. Was in Cuba in November, very nice. Friendly people, zero hassles and not a jet ski to be seen. Just booked a flight to Puerto Rico this morning, flying out on Feb 24th. My passion is fishing and it would appear there is tarpon fishing second to none just off the coast of San Juan. Was going to go to the Florida Keys but the flights were almost the same cost, car rentals are about 1/3rd the cost and fishing charters 1/2 the price of the guys in Florida.