I wasn't meaning to say that they would be slow. IMHO, 20 minutes is pretty darn good compared to the boats, and even not bad compared to most bus trips when you factor in wait time. And they'll be consistent: once you size up the queue, you'll be able to predict your arrival time pretty accurately, without worrying whether the next boat or bus will arrive in 5 minutes or 30 minutes. I'm expecting queue time to be pretty low, except at park exit.