Hubby went snorkeling and had a wave runner at Princess Cays in Nov. He loved the wave runner and felt it was very worth the $45. We were on the second tender over and had our pick of seats. It also got him in snorkeling very early. Others who got over to the island later said they had a hard time finding seating. They also said they didn't see any fish. He went in snorkeling after lunch and saw no fish, but did see them in the a.m., so I'm guessing with all the people around, it scared the fish away.
I, on the other hand, chose to sit in a shady lounge chair, near the snorkel shack and the bbq and the band, and suck down melon coladas all day while reading. Princess Cays was one of our favorite parts of the cruise.
We should mention that we both have very high-stress jobs and generally, a fairly stressful life (then again, who doesn't have a stressful life). The utter relaxation allowed on Princess Cays was truly what we needed.