Just got back from a trip to a place about 20 miles south of Playa del Carmen. Reef wasn't terribly exciting but the cenotes and Mayan ruins were. Cozumel is far better from a reef point of view.
Here is the link (cenotes are in galleries 2, 3 and 4):
http://www.divepics.ca/documents/mayanriviera1.html
If you're interested in the resort (Grand Sirenis) or Chichen Itza, i put some pics up in the first gallery here:
http://www.tripshots.ca/
Heres a couple example pics:
steve