Snorkeling excursions- here or Grand Cayman?

Just booked a new cruise! We will have my sister and family along. First Caribbean cruise for them and they would like to snorkel.

Last night watched an HGTV show on buying a place in Cozumel. They talked up the snorkeling.

We have been to Cozumel, but not done snorkeling here. If you had to choose one place to snorkel would it be here or Grand Cayman? We will stop at both ports.

If you would recommend Cozumel, who would you recommend going with? All the "kids" are older. 21, 19 and two 17 year olds.

Thanks

Even after the hurricane a few years back, Cozumel is still great for snorkeling and it would be my choice. Great coral snorkeling.

Grand Cayman is good for sandbar snorkeling for the stingrays, etc.

In Coz we like to snorkel from the shore at the Money Bar - clear water you enter via steps plus great facilities and only about a $10 cab ride from the piers.

In GC we have twice done the stingray and snorkel tour offered by Moby Dick - great service, un-crowded smaller boat; Mark the owner does a great job.