When we were deciding between resorts, I made a chart of various resorts in Cancun and Riviera Maya comparing some of the stuff we cared about. Don't know if it will be helpful to anyone, but I thought I'd share it. We compared:
Riu Cancun, Caribe
Sandos Riviera, Playacar, and Caracol Eco Resort
Barcelo Maya Beach, Costa Cancun, Tucancun Beach
Gran Caribe Real
Dreams Cancun, Riviera Cancun, Tulum, Puerto Aventuras
We weren't able to fill in all the blanks. After we did it, we also started looking at whether they had a maximum percent of guests who could stay at other resorts (the Riu Resorts did, which ruled them out for us because we didn't want to stress over that).
Hope this upload works--it's my first time, so bear with me!