I've been. We rented a car and drove down. It was really beautiful. If you go to Tulum Beach you'll probably see some nekkid people.
We went to Chichen Itza on a different trip. It was even better but we were exhausted by the time we were through. Christ my legs were sore. If you go with a tour group/bus you can't leave until the set time so it's better to drive your own vehicle.