Akumal is our favorite place along the coast. I agree with you about the reef and cenote diving. The only difference is that we only saw big fish on the reef and few if any small ones. What the divemaster considered a great dive was just ok to us. We can do as well or better by snorkeling at Akumal.
You mentioned that the beach is good for a Corona commercial. Actually, the first Corona beach commercial was shot just south of Akumal in Soliman Bay. I guess that they agree with you on the quality of the beaches on that part of the coast. I know that I do! One restaurant that we really liked was that was not on your list is Turtle Bay Cafe, it is THE place for breakfast.
Next time you go back, try to time your trip for either June or August. The turtles will be laying/hatching all along Half Moon Bay and Akumal Bay. The CEA holds nightly turtle walks at those times that you can join. Well worth the time and money. Here is a link to their site,
Centro Ecologico: Akumal, Mexico, Ocean Research, Environmental Education, Sea Turtle Protection, Marine Research. Great organization doing their best to protect the turtles and the reefs. Very deserving of our support.
Glad you had a good trip and we will be there, again, in early May.