we did it once and will not do it again, your time is so limited with the excursion. You can do it easily and cheaper on your own. All you need to do it budget your time, you grab a cab at the pier, go to Red Hook Harbor, the ferry for Cruz Bay leaves every hour on the hour- so plan your cab ride from Havensight accordingly-its about a 20-30 minute cab ride. Once you dock at Cruz Bay, walk the pier, grab a cab to one of the many beaches. Trunk Bay is gorgeous but it can get very crowded. go to www.vinow.com for beach and ferry information.
I thought the excursion was very nice personally. We really enjoyed the ship's excursion and felt we had plenty of time at the beach. Trunk Bay is absolutely beautiful, the best beach I have ever been to in the Caribbean. The only downside to the excursion, was the restrooms and outdoor showers at the beach were horrible and VERY dirty. I wrote a letter to the US National Park Service which runs the facilities after our cruise complaining about the facilities. 2/3 of the Island of St. John is a US National Park, and the facilities at it's most beautiful beach should not be kept in such filth! I hope they have cleaned it up in the last 2 years.
Majesty of the Seas - 10/03 & 02/07 & 11/08
Enchantment of the Seas - 10/04 & 10/11
Mariner of the Seas - 10/05
Vision of the Seas - 10/06 & 09/07
Carnival Liberty - 10/07
Adventure of the Seas - 9/08
Ruby Princess - 12/09
Voyager of the Seas - 9/10
Carnival Spirit - 11/10
Oasis of the Seas - 9/13
The one time I did an excursion like this, there was plenty of time there. It's actually nice, the planning is all done for you and you don't have to worry about the travel to and from there, its a nice way to spend the day and see another beautiful island.