We only booked 24 hours prior to arrival on the internet when we were in Playa del Carmen. 90% of all hotels were fully booked. Sina's location is good: just 5 minutes from the main road with frequent bus service to eithet down town or further along the hotels zone, ca. 15 minutes from Plaza Caracol, a big shopping Mall. There is a swimming pool and a fantastic view of the entire lagoon.
The recption staff was efficient and friendly. The suite, which was really too big for two of us, consisted of a living/dining room, kitchen, 1 bathroom with shower and 1 toilet and 1 bedroom with a/c. The room we had was downstairs and rather dark and depressing. There was a small TV which did not work initially. We phoned reception, staff came and explained that we had to run the a/c for the TV to work!