We came to this lagoon after snorkeling in Akumal Bay, so we automatically compared the two. While Akumal Bay is better for visibility and the sight of rare marine life (turtles, eagle rays and squid), the lagoon has a variety of reef fish that you don't see in the bay.
The place has its unique charm, with secluded spots, nooks and crannies to explore, but some may be murky due to vegetation, so visibility may be affected.
The facilities offered (clean washrooms, lockers, showers, equipment rentals, palapas etc.) are a welcome addition to a natural attraction that sees quite a lot of people. Very civilized and accomodating.
Don't forget your eco friendly sunscreen, much needed for the exposed body parts in the tropical sun. Enjoy.