My husband and I just returned from a fabulous 5 night stay at the JW Marriott. My husband stays in hotels 100+ nights per year so he has a fairly extensive basis of comparison. We used points for the stay and chose to upgrade to the Club 91 "all inclusive option" which for us was well worth the cost.
Overall, the property has a peaceful, elegant, and relaxed vibe. There is no music blaring at the pool and guests seem to be primarily seeking relaxation. We heard guests speaking Spanish, German, Italian, and English which contributes to a cosmopolitan sort of feel. Walking down the beach to the south you encounter the opposite at the Oasis Hotel- music blaring, guests dancing, organized games on the beach.
Club 91: If you're primarily going to stay at the hotel, it's worth it. If you're planning lots of excursions and want to eat at different local places, it's probably not. For the $100 per night we received free airport transfers, check in/out on the 14th floor in the Club 91 lounge, a room with a larger balcony on the 14th floor, 5 food "presentations" daily, free drinks from 6pm - 10pm, and free use of the sauna/steam room in the spa. Service in Club 91 was wonderful. Employees always greet you with a smile and were friendly and courteous. Cesar, in particular, was wonderful. He greeted us by name and made an effort to learn what we wanted to drink nightly. We thought the food was very tasty and fresh. A chef was constantly replenishing it. Following are a few things to consider when deciding whether or not to book Club 91. First, you must consume all food in the club. No sending your hubby down to grab a tray and bring it back to the room. No bringing drinks back to the room (other than a disposable cup of coffee, bottled water or sodas) to enjoy on the balcony. They do enforce this. The food portions are "sample or appetizer portions." You are welcome to serve yourself as many portions as you like. Also, you have to watch the clock a bit as the food presentations are offered at particular times. For example, lunch is from 12 - 2:30. So if you're down at the pool, you will need to leave and come up for lunch during these hours. It was fine to show up in your swimsuit, coverup, and flip flops during the day. It was nice to be able to grab bottled water and sodas anytime during the day to take down to the pool. Also, if you have kids, it may be hard for them to find things they'd like. Lots of fish, chicken, beef, salad, shrimp, etc.. I know my picky kids wouldn't have found enough they'd like.
Room: No complaints. It was perfectly clean, comfortable and soundproof. The rooms on the 12th floor (really the 13th, but like most hotels, there is no 13th floor) and 14th floor have deeper balconies than the rest of the hotel. One thing to consider when checking in is that there is a hotel under construction on the north side, Secrets. I don't think you'd hear any noise as the structure is all in place, but if you don't want to look at it, you might consider asking for a south facing room.
Location: Great. It's on the south end of the hotel zone so it's far removed from the noise of the party areas further north. Beach area in front of hotel is awesome with lots of loungers and umbrellas. Red flag was out the entire week, but most days you could still go in if you're a good swimmer and comfortable with diving under large waves.
Spa: Beautiful! They have the most beautiful indoor pool I've ever seen in a hotel. It's large enough to swim laps, but what makes it most special is the view. There are floor to ceiling windows on three sides. You can't see the beach, but you can see the lagoon. Beautiful at sunset. Jacuzzi is super large (30 people capacity) and hot. The workout area is nice. In addition to cardio machines, there are free weights and benches for lifting.
Tips: Consider picking up liquor at the duty free in the airport. We walked across the street to 7/11. They carry hard liquor and beer, no wine. Also, don't be afraid to use the bus. The stop is right outside the hotel. All buses go the same route so you can't get lost. They take pesos or one US dollar per person. They're clean. Hold on though. They brake suddenly. Driving in Cancun seems to be somewhat of an adventure so keep a sense of humor.
In conclusion, we would not hesitate to stay at this hotel again. Friendly staff, beautiful grounds, and location make this a winner.