I have been to Riviera Maya twice and like the "travel by your self" experience better than the all inclusive one. I would consider staying in the hotel for 1-2 weeks if I had children, simply because everything is organized.
The plus side:
Great room, (standard double with garden view), nice pool area and direct access to a clean beach. Everything was clean and modern.
Central location with shopping, restaurants, night clubs etc nearby.
Fantastic breakfast with alot of choices.
The gym was also appriciated.
The down side:
Slow wifi - not included
A little bit rude reception staff
ATM only provides US dollars and the exchange office in the hotel has hilarious exchange rates
Some of the taxi drivers provided by the hotel tried to hustle us