The Good :
Hot & Dry tarmac grip : It grips well, probably at satisfactory level... but Nitto Neo is better. But it is UHP type... that I can guarantee.
Wet tarmac - Surprisingly good (very good) hold and doesn't hydroplane much even through 1/2inch puddles.... before the thread hits 50% use.
Braking : Excellent.
Comfort : Yes. Soft sidewalls on 55profile. Goodly comfortable... this. UHP what?
The Bad :
Steering feels like it fell asleep for a moment, that steering response lag. Thanks to the soft sidewalls of these KU31s, you can't have that sharp steering response like you can with Nitto Neos.
The Sound of Tire when you're nearing 50% use and the tarmac's cold... but it's not so bothersome because if this start to start... it's a sign that the KU31s are in good grip period.
The ugly : ... I don't know...
Haven't seen any sidewall crack (Hankook Meo), swells (Dunlop D01), rubber chips (Michelin PS3) or deformation (Silverstone FTZ) yet on these rubbers.