I would definitely recommend the Sole Resort. It's about an hour south of Cancun.
NOTE: It took an hour and a half to get through immigration. The lines were endless and there weren't enough custom’s officials to handle the hordes. I heard other folks say that it has taken them three hours to get through immigration. I guess it depends on how many flights arrive simultaneously.
On a cheerier note, we stayed one night in Cancun at the Intercontinental Presidente hotel, which was part of a package RCI found for us that included a vastly reduced airfare with the one night in Cancun. I arranged a private van to transport my husband and me from Cancun to Tulum the next day. You don't need to convert currency into pesos either in Cancun or at the Sole resort. US money and credit cards are widely accepted.
The resort is beautiful! The staff was outstanding and the accommodations were very nice. Each room had its own balcony with a hammock and a table and chairs. The resort is impeccably clean and seamlessly run. The concierge can arrange any type of tour you are looking for. The food was very good; there was a great variety in several restaurants.
There is a lovely little chapel on the grounds near the pool and main lobby. We witnessed a beautiful wedding one day.
Plan on taking a brief rain shower every morning for about 15 to 20 minutes. Another plus for me was the fact the resort is all-inclusive, which fits me perfectly-no cooking, food shopping, or restaurant search! It was just a perfect week of relaxing, warm weather, and friends. Enjoy!