2 weeks of commuting on the Schwalbe Kojaks and I'm very pleased to report that they've held-up admirably. Not a single nick, hole, or cut in the tire casing after rolling through broken glass, sharp rocks, busted up metal and plastic bits strewn in the road from car accidents, and all sorts of unmentionable crap one finds on city streets. I've concluded that they must made of indestructible compound taken from crashed UFOs.

I have to give these tires 4 out of 5 stars for their durability, cornering grip, and ride comfort. However, I'm not completely sold on their touted performance. The rolling resistance is unusually pronounced for completely slick tires. My Primo Comets with their herringbone patterned tread accelerate faster and coast longer without bleeding speed as quickly as the the Kojaks do. I guess you can't have it all.

Anyway, the Kojaks are superb dry weather tires for commuting (won't speak to their wet weather characteristics yet). They look awesome and ride beautifully (you'd never guess that they were 32mm high pressure slicks), and emit a pleasant humming sound at speed on smooth surfaces. Keep them inflated above 90psi at all times (95psi is their max), otherwise their rolling resistance gets progressively worse.

If you want all-out superfast tires, get Primo Comets or Panaracer Minits, but expect to patch more punctures...a LOT more.