I've warped all of them. Powerslot, Brembo, Bradi, and Stoptech (cyro treated to boot). Didn't notice any difference in performance from just the rotors. But I liked the Stoptech's the best: two piece aluminum hats for the stock brake system.
Well, I take that back. I did notice a performance difference. The stock rotors weren't too good at the track. Rotor temps were always the highest. According to my measurements, from my memory:
Stock rotors hovered around 520 degrees.
Powerslots around the same, too close to call.
Brembo/Bradi around 490 degrees
Stoptech around 475 degrees.
All of my measurements were taken with different kinds of tires and pads AND on different days AND in different weather conditions. How's that for scientific!!
I was the most hard on the Stoptechs though. Probably because I'm a little better as a driver and am more confident in the cars ability. The time I warped them, it was because I left my foot on the brake peddle while talking with an instructor. My bad. The next session was like being in an earthquake.
BTW, all of the rotors, save the Brembos and OE, were slotted.