We stayed at the JW Cancun a few years ago. Very good memories of our stay. This is a beautiful resort hotel; great selection of pools; good selection of restaurants. Nightly live music in lobby and local cigar rep hand-rolling the tobacco. We never felt the need to venture outside the resort. First class service by all employees. Also has the CasMagna Marriott nearby to explore. Enjoy!
Cancun is great - are you worried about kids there on spiring break? Unless you are going to the same places they are, like cheap hotels and wet t-shirt contest nightcliubs, you will never see them. My family has stayed at the JW in Cancun for the last three years, and it's never been a problem.
We really like Cancun. As long as you are not looking for an "authentic Mexico" experience, you will not be dissapointed. There is a bus service that runs up and down the strip that costs $0.75. The busses run constantly, so you can go anywhere and see anything in the hotel zone very easily.
I have stayed at this hotel twice and loved it. Can't wait to go back. You can see my review on TripAdvisor. I paid extra for a 3rd person to be on the Club level and it was well worth it. We never had to leave the hotel for anything. They feed you very well and the open bar in the evening was a plus. The staff was top notch and the gym was huge. We did not try the spa, but have heard great things about it. If you just have to venture into town, there is a bus stop at the end of the drive to the right. It's cheap, fast and safe. We went into town one time and that was enough for us. I felt like I was in a bad version of Vegas.
We also had a fantastic family stay at the JW. We were two adults with our teens, which was great, but I would like to go back without the kids. Its no where near the craziness of Spring Break. We did do a day trip to Isla Mujeres, which was fabulous. The staff at the front door who hailed our cab also gave us towels to take with us.
We did Club 91 which was awesome, but we were on points, so only paid for the upgrade.
For a details, check out my review on Tripadvisor.
Have fun, you won't regret it.