The beaches are better to the south of the island, if that is a consideration. And the boat rides are a lot shorter to the dive sites...At Allegro, the boats typically return to the hotel during surface intervals (only for a few minutes) and then between the morning and afternoon dives. Pro Dive, at Allegro, is a very friendly, nice op, in my experience. The hotel itself is nothing really to write home about--it's hey day was probably 20 years ago, but we spent some time there during the holidays, and it seemed like there was a fair amount of money being put back into capital items, so they were sprucing the place up. However, it is not the Riviera Maya, so don't expect a lot of granite, marble, etc. It is finished rather modestly. And the food at AIs is mostly buffet, so if that is OK, you'll be fine. When we were there, we did fine with the food...but it can get a bit monotonous, in terms of selection, and overall taste...
The other thing is that like many properties in Mexico, the soundproofing is not like many of us are used to--you can hear things from other rooms if folks make noise--and if you are on a top floor, you have a palapas roof, which definitely doesn't dampen a lot of sounds (birds, etc., early in the morning). Of course, as a diver, I was always up early anyway, so it didn't matter....we were the people trying not to wake up others.
I know that doesn't sound like a ringing endorsement, but it is also not as sketchy as this might read. I love the staff at the hotel--they were very accommodating, and work their butts off. They do the best they can to make sure your stay is great. And I really do like Pro Dive. The staff there were the same way---wanting to make sure your dives were good. I would have no hesitation at all having a family member train with them.
The beach at Allegro is one of the better ones on the west side of the island. So overall, it is a good option, particularly since you are looking at a package deal. We have found overall that while we can do AIs, our preference, when feasible, affordable, etc., is to stay closer to town--not in an AI, and to dive from small, fast boats. But I would go back to Allegro if I had some of the same considerations of cost, package, etc., and would not have concerns about it at all. The point for me is to be able to be on Cozumel. After that (with some floor for comfort, diving/safety, amenities, etc.) it is all gravy.
One thing I will say is that if internet is necessary, it is extra, and expensive--$20 per day, or some discount (but still expensive) for a week. I think your son would have fun there--they do a lot of activities--he may even forget the video games for a while.
All of that is a long way of saying, "it depends on what you are looking for." I'm not sure that is helpful, but at least it gives some flavor...
