The last year or so I've been experimenting with some of the fletching styles in Jim Hamm's book, including a straight 2 fletch. Sometimes they are dead on accurate, then out of the blue, way off target. And also a little disturbing is the lack of rotation--kind of like trying to hit a knuckleball. I'm sure both problems can be alleviated by adding just a little helical spin.
The ease and speed in making 2 fletch is nice though.