I have one up in the classifieds right now. You can do four fletch, one at a time or two at a time depending on what configuration of four fletch you want. They are easy, and I would think they would be great for kids or novice fletching their first few sets. They are also great for field expedient fixes.
I like mine, I just dont use it that much, and like mentioned above, the forward tip of the feathers can get screwed up if you are meticulous. Overall, if you do a lot of back country hunts it would be a great thing to have in your pack.