I've stayed at the Silversands resort. PM me if you want to know more about my experience there. We have enjoyed the Secrets resorts we have stayed at near Cancun. When we were down there on our honeymoon a couple years ago, we went on a cultural excursion to Coba to see the ruins, and then we went and visited a legit mayan village in the jungle where they sleep in hammocks and have panther attacks, then went to another village and went through this religious place they have with some waterfalls. Pretty eye opening experience.
Main advice for travelling down there: They have a safe box in the room, use it. Set it to a code that both of you know and don't say that code aloud while you are there. I've never had anything stolen but known someone that had trouble one time. Put your passports in there and don't take them out, sounds logical but you don't want to screw that part up. Also, make sure you have a credit card with a fairly high limit. A person in the group we were travelling with last year fell at the resort and hit her head, she had to go by ambulance to the hospital in Cancun. Her husband went with her, but before a doctor would look at her at the hospital, they had to put a hold on the credit card for a significant amount(between 5 and 10K).