We just stayed at the Hotel Cozumel earlier this month. It wasn't a "bad" hotel, we stayed because it was on the cheap side and that's what you end up with. All of the hotel employees were nice and tried to please.
Like someone else said, they have a sand area to play in next to the ocean but you have to go down steps to get into the water. No actual "beach".
Are you planning to have your 16 year old watch the 2 year old while you dive or planning to hire a sitter? We did the sitter route (our kids are not toddlers). Neither sitter we used spoke much English, which some might find frustrating if they can't speak any Spanish.
The rooms were adequate, not extravagant but clean and had telephone, tv, and ac. The pool was big and there was always plenty of room for the kids to play. The shore snorkeling wasn't bad for being right at the shore, saw plenty of fish.
The food (if going all inclusive) wasn't bad, not a huge amount of selection but we were always able to find something decent. They put on a show every night, the kids enjoyed it but it was kind of like a high school production and in the week we were there there were a couple of repeats.
The location in town was kind of nice, we walked to the shopping and pier area a couple of different times. You are also close to the "Mega" store and they had about anything you needed and at reasonable prices.
The on site dive operator will let you do shore dives for like $6 or $7. Was a great opportunity to do a check out dive and get the cobwebs out before doing the boat dives. We did not use the on site operator and can't say anything about how well they did. Their boat groups looked large, and the fast boat we took always beat them back to the hotel by at least an hour (more time to enjoy while on vacation).
Anything specific you were looking for about them?
