I knew a bunch of people who paddled yahoo's. About as maneuverable as a ducky, the hulls are empty and need to be drained and eventually the plastic will wear thin (they aren't really meant to hit rocks) and then it's trashed. I think the are quite a bit faster though. You can front surf some longer waves too.
A few people could actually roll them, but then it leaves you wondering why they weren't in a closed deck whitewater specific boat. If you wanted to paddle a single person boat without having a roll duckies make way more sense to me, with durability being the biggest factor.