I traveled to the Riu Caribe Cancun from December 22 - 27 2012 with my wife and parents who are in their 70s. I was a bit reluctant having been to Cancun before and knowing what a party town it is. But the Riu Caribe Cancun was a great choice and catered very strongly to families, with still plenty of entertainment and bars for younger people. The hotel is also on the northern end of the hotel zone so it is not immediately close to a lot of bars and a rowdy night life area.
Location - the location on the northern end of the hotel zone means it is a bit quieter area but still lots to do and the beach is pretty narrow. But that makes it great to be able to see the Lagoon on one side of the hotel and the Caribbean on the other. All we had to do was step outside our room in the open-corridor and take some great photos of beautiful sunsets over the lagoon. One thing we loved about the location is that it is only a couple of blocks from Playa Tortuga and the terminal for the Ferry to Isla Mujeres. Be sure to take the Ultramar as the Mexicano costs the same but is literally 4 times slower. They told us this was because there was a problem with the engine but the Ultramar is sleek, modern, and fast.
Service - the service was impeccable and we left feeling like we had met friends there. Franky at the pool bar which is the steakhouse restaurant in the evening when he works is a lot of fun and will make you some great drinks. The front desk staff was also great as they very efficiently took care of changing our room when we did not get the one initially that we had reserved. They took care of everything while we were out the next day on a tour and had our luggage waiting for us in a room with a fantastic view of the pool and beach.
Restaurants - there is one main buffet restaurant that gets pretty wild with all the people going through. As expected the food is mediocre at best. But the service is excellent and overall it is much better than the majority of buffet restaurants at an all-inclusive. Be sure to reserve the Mexican restaurant as the atmosphere, service, and food is excellent. They take reservations from 07:00 to 11:00 a.m. every morning for the three specialty restaurants that are the Mexican, Asian, and Steakhouse. We did not eat at the Asian restaurant but the menu looked appetizing. The Steakhouse provided superb service and the steak was ok. But the atmosphere is not to be missed as it is an open-air restaurant by the pool and views of the Sea (if you can see it in the dark).
Pool - the swim up pool bar is excellent and the pool itself is large and spotless. There are very comfy seats in the water to stay cool. The staff does a nice job of hosting pool games all day that are entertaining but not too loud and obnoxious. There are plenty of chairs under the shade of an umbrella if you get there early. We spent an entire day just relaxing, swimming, and drinking. It was one of the best days of the trip!
Beach - there are lots of beach chairs crowded together because the beach is so narrow. The color of the water is a beautiful aqua blue-green, as seen in photos of Cancun. There was some seaweed but the staff did a good job of trying to keep things as clean as possible. They also have a booth with a good selection of water sports tours from trips to Isla Mujeres to Jungle Tours on Waverunners. There is also a real nice beach bar that is away from the pool with a nice view of the beach. We were therer at the end of the day and it was quiet with great service, as usual.
Spa - my wife and mother enjoyed a pedicure and manicure at the spa which they said was excellent. For the location, it was reasonable priced at $60 for both the manicure and pedicure.
Overall we had a very enjoyable time. I would recommend this hotel and would go back myself the next time we are in Cancun