Have never used them. No treadwear ratings that I can see on the site. Price is pretty darn good though and the tread pattern looks nice. Compound isn't recommended for road use which means it should be a fairly good tire to run in the summer time.
**** that's dirt cheap for a track tire. only "track" tire i've ever used was a direzza DZ102 and it was great for the first 10k miles. then it started to wear horribly with these lumps all over the outer edge of one tire and the tread was gone in barely 18k miles. so never again with those.