Anyone used one of these...
 

It takes me hours to clay the truck by hand. Just wondering if this would be faster. I'm kinda hesitant to rush this process, but I've used their other products and trust them.

http://classic-motoring.stores.yahoo.net/popadclap.html

Hours? Why so long? Don't think it takes me more than half an hour to do my dad's, hour at most.

Granted, I don't know if I'd use something like that. Wouldn't you have to be constantly turning the DA off to flip/mold the clay to a cleaner section? Plus, I usually listen to how the clay "sounds" when claying. It's usually a good indicator of when you reach a "dirty" part.