Xcaret is 10 minutes south of Playa del Carmen, adjacent to the industrial pier Carnival used to dock at when the Holiday stopped there.
I've been to Xcaret twice but it's been 10 years since the last time. It requires a lot of walking. Things are expensive (sodas, beers, snacks, souvenirs) and they have restrictions on what can be brought inside such as suntan lotion that isn't ecologically approved. Of course they conveniently sell 'approved' lotion.
The beach area was pleasant and you can do an underground river tubing excursion. They have the dolphin tours too.
But frankly unless my ship docked over on the mainland I wouldn't go to Xcaret because I can do just about the same things on Cozumel. And Xcaret does require a ferry ride from Cozumel, which is often a motion sickness episode for many passengers. Note that Royal Caribbean makes it a point to mention the ferry ride can be a problem more than once on their Xcaret excursion webpage
, and they also mention a person's medical and physical condition.