Mexico

[Oilers]

I am planning to book a trip to Mexico for my family this August and I am wondering if you guys can help me making my trip more enjoyable.
The place is Riviera Maya and the hotel is Gran Bahia Principe Copa. Have you stayed there before and how was your experience? Is there another hotel you would recommend? I am looking at 4 or 5 stars hotels only.
What is there to do in there? What are must see sites? I am bringing my kids (4 and 2 years old). I am trying to find things to do that are suitable for them as well.
That's all I can think of right now. If you can think of something else, please let me know. Mucha gracias!!!