Hey John!
Xel Ha is more of a day filled with water based activities - a lot of snorkeling and being in the water. Older kids usually get a kick out of seeing all the fish, but sometimes younger kids don't want to get in the water (cold, fish are scary
, etc). Xcaret is more of a "Mexican Disneyland" kind of place - more land based activities. Animal exhibits, a butterfly garden, and the opportunity to snorkel is also there as well. Plus, there is the night show at Xcaret, which for many is quite a thrill. Perhaps talk it over with the parents of the kids as they know their children best - if they are true water bugs or would prefer being on dry ground more than in the water.
Hope that helps!
