It was addressed sufficiently for me. Did you even read 5 Shot's review? Here is what I have been referring to:

"When I applied them in a straight fletch configuration I found that out of properly
tuned bows they provided as much control as a 5” feather fletched with a hard helical. I
also noticed that when I shot a group of broadheads at ranges out to 40 yards, the
feather fletched arrows and the Quick spin fletched arrows shot to the same point of aim.
I found this sort of amazing in that the feather fletched arrows weighed an average of 30
grns less that the Quick spin arrows. Most of the broadhead shooting was done with
Muzzy 3 blade 125 grn heads. I know this head very well and have found it to be
accurate, but normally you need to use at least some helical to get them to fly well. By
using the Quick spin vanes fletched straight, they controlled the arrows as well as the
same shaft using either 3 4” feathers or four 3” feathers, both fletched right helical. "


As far as feathers are concerned, I know nothing. I have no interest in ever using feathers, so what they do straight fletched is of no concern to me. The quikspins are; however, because they do appear to give the archer something that vanes cannot. The price is just not an issue to me. If it is with others, fine.