Well I still have a lot of time to decide. But I hear so many people singing the praises of RP. I like what I've read about it so far. In the end I'll probably see if anyone has done a comparison of Mobil1, and RP, and see how they stack up.
So as of right now, I don't have statistically proven reason for picking RP.
I may decide differently when the time comes to make that decision.