Would you expect to go to a 5 star Thomsons platinum hotel and get robbed by the staff working there? if the answer is yes then by all means go to the Riu Cancun. If the answer is no then avoid it like the plague. My wife and I went there for two weeks in September this year. We were there with another two couples and out of the six of us four of us were robbed. In the two weeks we were there we spoke to six other parties who had also been robbed including one couple on their honeymoon, who in fact got married in the hotel. How low can you go to marry someone and then rob them on their honeymoon? And don't think that the management don't know what is going on. they know absolutely what is happening and refuse point blank to do anything about it. My friend had a gold watch, two gold bracelets and her camera all stolen out of her room. A ROOM THAT WAS SECURELY LOCKED AND COULD ONLY BE ACCESSED USING A KEY. We had two hundred dollars stolen from our room, but after seeing the way our friends had been treated the day before we didn't even bother to report it. AVOID!!!

We booked 2 rooms all-inclusive at the Riu Cancun Sept. 15-21 through Amex. The stay was overall enjoyable.
The hotel premisses are well depicted in the travelers' pictures. It is very clean, both in common areas and in the rooms. We were told it was only 5 years old but we are wondering if this is true, because it looks dated and worn out in some places. Or maybe they used cheap materials.
The personnel is extremely polite and helpful. You can see cleaning crews at all time keeping the premisses spotless.
The room :
It was a regular room (they all face the ocean), decorated in blue tones, with 2 double beds / night stands and a little table, a chair and an armchair. On the balcony, there were 2 plastic chairs, a plastic table and a clothes hanging thingy (very convenient). The TV had a large choice of channels, including TV5, for French-speaking guests ! The contents of the refrigerator were included in the all-inclusive package, as well as the liquor dispensor on the wall.
The bathroom was large, adequate. However, it only dispensed shampoo and lotion, no conditioner. Ladies, bring your own conditioner. There was no light in the bathtub/shower nook, so it was a little dark when showering. Also, on the down side, there was some sand in one bed in the other room.
Something bothered us during the whole stay : the smell. The detergent there are using to clean the common areas has a bleachy/rotten smell that is emphasized by the heat. It also smells a little in the room. We knew it was the type of cleaning liquid they used, but it was still weird.
The A/C works well, although it is a little loud. It was not working in the elevators when we were there, so the air was stuffy and incredibly hot in them.
Outside :
The pool areas are clean and nicely designed, and it was not too difficult to find lounge chairs. The beach is a little rocky, but it is the same with the whole area anyway. We didn't take part in any of the entertainment, but we saw guests having fun at the pool playing games and contests of some kind. It was not too loud.
The all-inclusive includes water sports, but this means basically snorkeling. It was never possible to use their kayaks "because of the currents, too dangerous". Maybe that was indeed the truth. it was September, not high season. But they didn't have many kayaks, from what I saw. We snorkeled but didn't see much fish.
The food :
We were surprised by the variety of the food offered in the buffets. Most Reviewers complain about that particular points in all-inclusive, but it was not bad at all. Not everything was good, but you eat well. We were very disapppointed with the restaurants, however. The Japanese and the Brazilian for which you "have" to make a reservation before 7 AM are not worth it. The Japanese is not typically Japanese and the Brazilian is a pale copy of a churrasquaria (almost the same food was at the buffet, we went and checked after dinner).
Internet access :
It is charged $3/15 mn in the sports bar / internet cafe, from 9 AM to 9 PM. They have about 7 or 8 computers. I don't know about the quality of wifi...
So, overall we had a good time and enjoyed the Riu Cancun despite a few glitches. Reasonable value for your money.

Off topic but important :
When arriving at the Cancun airport, beware of the guys who try to send you to a timeshare presentation and reward you with a free trip to Chichen itza or Tulum. When we declined the guy's offer, he immediately offered more incentives and said he wanted to give us a discount on the taxi to the hotel, if we could at least take his phone number and think it over. We agreed, he took us to the taxi station at the airport (it looked genuine, official) and paid "$50 instead of $55". Well, on the way back to the airport, 5 days later, we paid only $30 for a taxi ! Big rip-off. The guy's name was Fernando if I am not mistaken. He claimed to be working for the city, or the tourist department.

Booked this hotel based on previous reviews and the fact that it is advertised by the Tour Operator as - 'beachfront living at its best', 'classy' and 'breathtaking'. This certainly is not the case. If you want either of the above stay next door at the RIU Palace Las Americas.

Stay at the Riu Cancun if you want:

- A 5-Star hotel which is at the standard of a low grade, in need of refurbishment 4-Star hotel.
- An atmosphere designed for people who drink excessively all day, everyday.
- A swim up bar which is packed out all day with excessively loud, over-dramatic guests and surrounding pool water which looks as though one to many consumed drinks have been passed into it.
- Excessively drunk, loud, over dramatic guests running up and down corridors knocking on doors at all hours of the morning.
- A buffet restaurant which has about as much life in the food as a dead cockroach.
- Seriously, the list could go on......

The only good things about this hotel:
- Brazilian restaurant.
- Friendly staff.

Plus, to back up the concerns RIu much have with this hotel. The Riu Cancun and Riu Palace Las Americas are directly next door to each other and are both 5-start rated yet...Riu Palace Las Americas guests CAN use Riu Cancun, Riu Cancun guests CANNOT use Riu Palace Las Americas.

Just returned from the Riu Cancun(21\09\2008-01\10\2008).18 of us in the group,including some children.We went for my daughters wedding.Travelled with Thomson,long flight but worth it.Hotel was great,heard stories on tripadvisor,but speak as you find,and I found it great!!!.Room was large and clean,maid service was good.Pools were clean,stayed away from swim up bar,for obvious reasons.Spent most time around quiet pool,and hot tub.Cleaners and Gardeners on the go from dawn till dusk.
Food was good and varied,tried Brazilian restuarant,excellent,did'nt try Japanese.Bar staff very friendly and helpful.Food and drink available 24/7.
We were scattered all over the hotel,we were on 9th floor,grooms parents on 13th,others on 4th and 15th,daughter had a suite on 4th floor of annexe.This was good,we could meet up when we wanted,but had time to ourselves as well.
We did a couple of trips(xhel-ha/pirate cruise/shopping malls),my son did most of the trips.
No need to leave the hotel if you dont fancy trips.
Only tips I have are;
1.Use bottled water for brushing your teeth
2.Keep all valuables in the safe.
3.Enjoy yourselves