I will chime in, even though you know my experience.
I have the Zapper 300, and honestly I do like it. I was having a little trouble with it, but after some help here and a talk with the company, I think I may have the problem solved.
I am shooting CarbonAero Excel 400s with straight fletch. There does seem to be a slight heli, maybe 2 dg. There is no problem with vane clearence with mine. And, I can pretty much rotate the bow all the way around without the arrow falling off.