We took the jet boat out earlier this month. I though it was the way to go. It was a bit of a pain to derig at the take out, mix up all your gear, load it on the jet boat and then unload and separate at the top. However, I think overall you save time. For us, it was the same price to pay for the shuttle or the jet and we saved the gas on the shuttle. And, it's a cool experience... crashing up the waves, seeing everything in reverse and drinking with the gang. We used these guys, http://www.whitewaterexpeditions.com/charters.htm
and they were great.