I booked this trip as part of a 3-for-2 deal with Vallarta Adventures and it was pretty good. You'll be traveling with a rather large group (I think up to 150 people?), but Las Caletas is pretty big, so it doesn't feel crowded. We saw lots of dolphins on the way to the cove, and the captain slowed the boat down so we could get a better look, which was nice.
First off, WEAR SUNSCREEN. I guess I didn't reapply often enough, because my shoulders got badly burned. There is shade available; if you burn as easily as I do, take advantage of it. If you forget your sunscreen (or other essentials, like bug spray or a beach towel), they sell them at the pier and at Las Caletas.
The snorkeling was pretty good on the day that I went (I guess it varies). I saw a lot of different fish in half an hour. They could improve this part of the experience by having a book or poster identifying some of the fish common to the area, because I was curious.
I had a half-hour massage, which I don't recommend. It was just OK and the prices were the same as I pay in the U.S. You can get a much better deal in the city or the Marina. Save your money.
Lunch was pretty good. I took the paella cooking lesson, which wasn't so much a lesson as a demonstration, but it was still interesting. The food (including the paella, which had like seven different kinds of seafood in it) was very good. I loved the tequila cheese flan!
The nicest thing about Las Caletas is that it's very self-directed. You can be as involved or as detached as you want to be. I was kind of in the middle. I participated in a few things, then found a beach chair in the shade and read magazines for a while. The open bar was pretty good (weak drinks, though) and the service was mostly attentive. This is a great option if your hotel is not on the beach or doesn't have a good one.
The crew made the ride back to PV very entertaining with a Queen lip-synching show involving ... well, you'll just have to see for yourself. It was pretty hilarious. They did a good job.
This was not my favorite of the three day trips I took with Vallarta Adventures and I don't think I'd do it again, but it was very good.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.