I am very pleased with a pair of Power Ones put on for a track day at Brands hatch two weeks ago. Although I was VERY RUSTY to start, soon felt like a god.
Previous tyres were Dunlop RR's, which had very little grip until warmed up (but reasonably fast to do so).
However, I'm in clear need of damping setting adjustment. The edges of the rear are shredded and blue-ish as they have been spinning as I crack on the throttle and gently roll on power in the corners (and I never noticed). By comparison, I have felt this with the Dunlops, which gave me heart stopping moments.