Did Excellence Cancun in march, great food, great drinks, both party fun and relaxation if you want it. Took a bike tour a couple miles to the local touristy sales area and bought some souvenirs at the market. Bought a stone turtle off a guy on the beach next to the resort (not allowed on the resort). Took a tour inland to tour the cenotes (Zipline, cliff jump, swim, etc).
Always felt safe. Had private transfer from the airport to the resort provided as part of the stay, excellent driver that talked to us about life in Cancun, the area etc.
As others have said, don't go off resort at night, if you do, go to clubs with lots of people from around the world, and if you do that. . . Don't start shit with anyone and if someone starts shit with you be apologetic anyway and smooth things over with a drink!