Loved the Coba, no other vacation to Mexico has compared to the Gran Bahia experience.  Food and drinks were great with lots of choices.  Resort is very large and it will take a day or two to get used to it.  Pools are huge and clean, my favorite was the adults only relaxation pool.  Close to the ruins at Tulum, you can take a collectivo if you go out to the highway for $2 US.  Mini bar was re-stocked daily with drinks and snacks (chips and chocoloate bars).  Evening shows were good and the theatre is very large.