We used them for the dolphin swim we did this past December in Cozumel. LOVED THEM!! For the same price as the dolphin excursion that Disney books, we got the extra benefits of the following:
1 - Cheaper (loved that the most)
2 - Got to swim with the dolphins instead of just stand there (swim vs. excursion)
3 - free tix to see the sea lion show
4 - free entrance into the park
We will defintely use them again, whether we it's for the cruise or another vacation.
Also, I printed the vouchers off my computer for the three of us(print two copies - one for you and one for the place you are going to), so I had my tix immediately. They are very nice and helpful there too.
Can't say enough good things about them!!