Our two little pirates did the Pirate Cruise.
Worth the time? It will take half a day and its a matter of priorities. We are glad we did it because it gave us a morning without our kids where the hubby and I went and had breakfast at the Kona Cafe. But morning is also prime park time....we missed MGM almost completely this last trip, I would have liked to have spent more time at the MK, we missed a couple of things I would have liked to have done at Epcot and AK. We will be back in a couple years - and I'm glad we did the Pirate Cruise this time, but I wouldn't do it if I didn't know we were going back, or if the vacation had been a brief one (we were there for seven nights - had it been four nights I don't think the Pirate Cruise would have been worth the time).
Worth the money? Thirty bucks a kid for about two hours (but plan on the event taking four of your time - they are on the boat for a full two hours, but you need to get there, get there early, and pick them up). The kids get a sack of trinkets (mostly birthday party stuff - rings, spiders, superball eyes) and lunch. But what you are paying for is the experience. We thought it was well worth it, but I know $30 is pretty steep to a lot of budgets. Then again, its hard to say, my four and five year old have yet to give a coherent account of the event (I know most of what I know from people here posting accounts told by their older children), and they don't have any grasp on "was it worth the money" as money is still pretty meaningless to them.