The XP10 is a great pad for intermediate to advanced drivers. The operating heat temperature ranges stated from Carbotech, stand true except for the cold temp for the pad. The pad will bite flawlessly in California cold weather. Hell, it even bites better than my Stoptech Street Pads when completely cold. The pad has great fade resistance with consistent bite and feel. Initial bite does not result in a jolt, but rather a smooth rate of deceleration that helps keep the vehicle stable during braking. Replacements are needed often, sometimes as early as after 2 track days are completed. Of course these are under extreme circumstances. Other than that, this pad will fit a very broad range of drivers and vehicles.
The RP2 is a new pad introduced by Carbotech in late 2010. It is the endurance version of the XP12 (a more aggressive pad than the XP10). The RP2 surprisingly has less initial bite than the XP10 yet the pedal feel is just as linear. Overall bite was noticeably less but all you have to do is push the pedal a little harder. The RP2 pads do stay consistent over a longer period of time than the XP10 and I have personally done 6 track days on them without needing to change them. I have about 1 more track day out of the current set of RP2s. What is most surprising to me is the life of the pads. It is without a doubt a smarter choice to go with the set of RP2s. At the price point these are set at with over three times the life, the RP2 is a winner in my book.