My concern for looking at a tire that wears longer is that they need harder compound. Harder compound is less grip. Especially the F3 and F3-S need the grip and wet weather traction. The primary issue with the Kenda tire is it wears it the center. Wear will occur where the stress is biggest. In looking at the pattern from an aggressive start and 'burn out', there is a darker pattern near the edges. But the tire wears out in the center.
My friend Butch related that the carcass doesn't hold its shape at speed, allowing centrifugal force to stretch the center, with more contact force and stress going down the road. As we typically spend more time at highway speeds than doing a burn out, I offer that seems to be a more plausible explanation for the wear. He recommended running higher air pressure for the tire to hold its shape.
Since that time I've run 30 to 35 psi with better results. Somewhat counter intuitive but it works. We run our Spyders hard and typically get 13K to 17K on the Kendas. Yes, the center still wears at a faster rate but then the sides catch up. We've got about 120K Spyder miles on GS, ST and F3 models.
We did try a Kumho with better flatness in the wear pattern across the tread but the tire was severely out of round. Plus it had had lower traction. I find the KENDA to be a reasonable value while retaining OEM traction.