I experimented with 4 fletch arrows a couple years ago, and am hooked. For one, I can get 2 fletches out of a single full length feather, and since I use natural turkey feathers, I want to get all I can out of them.
As far as set up, I use the 4-90 setup, ariented in an X and get perfect arrow flight. I have no issues with feathers being noisy in flight.
I like the looks of the arrows, and they fly great even with the big wide 2 blade Zwickey broadheads on them.I put as much helical as I can get on them as well.