I have been to this All-Inclusive Resort twice, and must say it is a great value. It's about an hour trip from the Cancun airport. The grounds and staff are lovely and the rooms are very clean and comfy. The pools are beautiful, though the swim up bar can get a bit crowded.
In addition to Coba, you have access to the sister resorts, Akumal and Tulum. The beach is a short tram ride to the Akumal resort and is gorgeous; I especially enjoyed the little lagoon, which gives the feeling of seclusion.
My only gripe with this place is the food. Not that it's bad; just repetitive. If you're a wine person, you will be disappointed with both the red and white options offered with the all inclusive package. The other drinks are very good; I especially recommend the Sombrero.
I was especially impressed with the staff; from the host and hostess at check in, to the tram drivers, and even the gardeners, everyone goes above and beyond to make your stay a pleasant one. All in all, great vacation.