Lungbuster, I use the 4" quick spins on heavy shafts with fixed blade heads, and last year I used the 2.25"ers for NFAA dots, BHFS, they also work just fine for mechanical heads at 280fps. This year I've installed the 3.125's and will be using them.
I have made several comparisons with AAE's/Duravanes, and though some differences can be observed they are very small over hunting ranges. I took 8 arrows, CX 3D 200's, to the range on two days this spring, 2 with 2.25"QS/RW 1 degree offset, two with 3.125" QS/RW helical, two with 3.125" QS/RW 1 degree offset,and two with 3" Duravanes/RW helical. I shot all 8 at targets 60-80yds, several times, on both days. There wasn't one bit of difference that I could detect, with most shots in the inner 4 ring or the dot, at all ranges. But the QS arrows consistantly group better at all ranges,
Fletching them helical will slow things down a bit with the 4"er's, and cost you 4" with heavy shafts and up to 8" with lighter shafts at 65yds, for the most part, fletched straight, there's no difference at all.
Do I use them on all of my setups? No, as with mechanical heads there's not a dimes difference over hunting ranges. My 3D setup, a 62lb Vipertec with GTUL 400's, does not shoot detectably better at 3D yardages relative to my 4" Duravanes. But my hunting bows shooting CX Terminators, with G5's and Barrie fixed blade heads DO shoot better with the 4"er's fletched straight. Way better.
All in all, I've used them on various shafts from my 2-50lb bows, my 3-60lb bows, and my 70lb elk rig, from 250-300fps. Some show advantages, some do not. None have ever made a noticable noise.
Do they hold up well? No.
Are they worth the money? Sometimes.