Is Will a younger guy working his way around the world as a DM? My wife and I stayed at Dreams Nov 2006 and they talked me into scuba - did the resort course w/ Maya Diving. AWESOME TIME!! The instructor, Will I think, was great and we had some fun dives. Didn't do any cenotes.
One thing I will say after diving w/ Jason in PDC Dec 2007 - there is MUCH more life on the reefs in PDC than I saw in Tulum. However, I dove only twice in Tulum.
We did enjoy Tulum but once at Dreams you're pretty much there. It's a LONG walk to the road which is the highway. You can rent bikes but you're biking along the highway in to town which is about 1/2 hour. Personally I preferred the easy walk from our resort into PDC. More to do, better diving. However, the beach in Tulum beat the heck out of the beach at our PDC resort and you couldn't beat Dreams for a relaxing, peaceful, romantic getaway.