Pros: great beach location, short walk to snorkel off the Club Med property, Royal Beach Club is more intimate, good selection at breakfast and happy hour, all staff is very pleasant, concierge at main hotel are all well informed and helpful, fitness center is pretty well equipped, spa looked very nice

Cons: room never really felt dry, had to ask for maid service on 2 of the 4 days, concierge at RBC sent us in the completely wrong direction for a market in Old Cancun, some noisy guests - beware there is no carpeting so moving chairs makes a ton of noise at 6am.

This is our second stay and I would go back again. We have only ever stayed at the Royal Beach Club which includes a free breakfast and happy hour. There were lots of families there - toddlers to teens. I think couples would be happy there also.

Stayed 5 nights with two adults and two kids, 8 and 10 yrs old. Read earlier reviews which were pretty accurate to what we found. Hotel property is on par with most Westins, not a Ritz or Four Seasons, but not supposed to be. Rooms were comfortable, not many have balconies though. Service staff everywhere in the hotel was excellent. The advantage at this hotel is that there are a number of pools, nothing exotic, but plenty of space and you never had trouble finding a chair - on the beach or the pool, and the hotel was sold out. Other Cancun resorts get a crowded feel, but they have so much property that it isn't a problem at the Westin. Bernardo, our waiter near the beach/pool was fabulous, but so was just about everyone we met at the hotel. This hotel would be good for couples or families, and if the water is rough, which it can be in Cancun, you are a short walk to the Club Med beach which is more protected given a rock jetty that creates a bay-like area. You are also at the end of the bus route, but the buses come often, so you can get where you need very easily. We drove one day to Chichen-Itza, maybe would rethink that. Tolls were $20 each way, plus $90 for the rental car, and the directions weren't very clear from Thrifty.
Best restaurant we went to was Cenacolo, a nice Italian restaurant in the hotel district. Great food. Only drawback is while they welcome kids, they charge a full adult meal price (Cheese pizza, $17) so you get the point. Great spot for couples and and for families not worried about the price.
Also did the dolphin experience at the Isla Shopping Center and that was well worth the expense to swim with the dolphins ($135 per person). Great venue and nice staff.

Glad for all of the negative reviews b/c for the most part, the staff was on their toes at all times. The room was clean (my biggest concern after reading the reviews), the beach was great (huge and always had chairs available), and the pool was nice. We even thought that the food was pretty good. Careful of the expensive breakfast buffet at the main restaurant though - very good but pricey! My only real complaint was that one night we were without power all night long and it got very warm in the room. The staff all of the sudden was very unapologetic - don't know how often that happens, though. The town is definitely far away, for those of you who like night life, so be prepared for a 30-45 minute bus ride to get there. The bus is extremely safe and cheap - my sister and I rode late at night and didn't have any problems at all.

I'm giving the Westin Cancun 4 stars instead of 5 only because I think 5 stars should be reserved for ultra-luxury hotels, and while the Westin isn't the Ritz, it's still a wonderful hotel. I just returned from Cancun a few days ago, so I figured I'd write this review while the trip is still fresh in my mind. This was my first time ever in Mexico, and overall, it was a wonderful and memorable trip, and the Westin was the perfect place to stay. I'm sad that I had to leave.
NOTA BENE: This has nothing to do with the Westin... but BEWARE that as soon as you exit the Cancun airport there will be people trying to get you to take their taxis, shuttles, etc. DON'T TAKE THEM. They are scammers and will rip you off. They will appear legitimate and friendly, but they will charge you a ridiculous amount to take you to your hotel. There are large tour-bus-style buses that you can get on for much less money that will take you to the Westin. DON'T FALL FOR THE TAXI SCAMMERS.
That said, I will focus on the Westin. This hotel/resort is beautiful. The lobby and restaurants are modern, well-furnished, and clean. The pool/beach area is amazing. There are tons of beach chairs, umbrellas, etc. The pictures of the Westin that some people have posted don't do it justice at all.
The room I stayed in was super cute and well-decorated... white walls and beds, tile floors, LCD TV, spacious bathroom with tub and great shower. The beds were comfortable and had great pillows.
The staff at the Westin is ultra-friendly. While we had no problems, I felt that they would have catered to my every whim.
In response to some previous reviewers complaints... some people tagged the Westin as a "family" resort with lots of kids. No, sorry. There were hardly any kids there, and even if there were, who cares? They swim in the kiddy pool and build sand castles and don't bother anybody. In my experience, the Westin guests were typically in the range of 20's - 50's, cosmopolitan, and well-behaved. And thank goodness there were hardly any noisy, drunk spring breakers there. I'm only 28, but I really appreciated that this hotel was far away from the noise and drunken antics of all the spring break kids.
And in reponse to the reviewers who said drinks, food, etc. were overpriced. Well, this is true I guess, but what nice hotel DOESN'T overprice their food and beverages? You don't go to a nice hotel to get cheap food and drinks. Duh. And speaking of the food, one of the highlights of my trip was the Westin's buffets. They were to die for. The lunch buffet outside, which I indulged in twice, was amazing. Yea, it cost 24 USD, but who cares. It was sooo good. Everything in Cancun is overpriced because Cancun is a tourist trap, and they know that tourists will pay for it.
Some people also said the hotel felt "damp" or "humid." Yes, the air inside the Westin is a little humid, but guess what... it's on the water in Mexico. What do you expect? If you want super-cooled, climate-controlled enviroments, then stay in your house with the AC on and never go outside. Mexico is all about the heat!
The Westin also had reps from the various tourists companies around town that could sign you up for various excursions. I would recommend AquaWorld, and their Isla Mujeres and Cozumel day trips.
Perhaps the people who left negative reviews are used to a higher standard of hospitality than I, but I found the Westin to be a very classy, sophisticated, gorgeous resort. No complaints really.