some like them, some love them, others say they are just ok.
i personally have not seen them group any better than a regular 4" vane. I just use a regular 4" duravane for me, but i shoot mechanicals. If you shoot fixed, make sure you put some helical on the vane
I shoot Blazers...love them for fixed-blade heads. I like them even better with offset vanes...shoots tighter groups for me. The only issue I have ever had with them was a clearance issue on my ripcord rest. Finally got that all straightened out and went right back to the Blazers.