Quikspin Test and Review:

Also notice the greater loss of speed (shedding of KE) downrange, and the change of FOC.

http://www.technology-for-hunting.co...nes_review.htm

Even with the pros and cons determined by the test, the vane appears to perform well enough to use, but maybe not greater enough for your average shooter to want to spend $20.00 for 36 vanes, when 36 vanes of another good type and brand can be purchased for $6.00, or $10.00 for 100 vanes.