I don't get why you asking, its blindingly obvious. Personal choice.
A) Pirelli are more expensive
B) which adds up when they don't tend to last long for that.
C) The profile isn't to everyone's liking
D) SC's are **** in the wet (this is the UK).
E) there's barely a bad tyre out there...from any leading co.
F) carcass construction is different, hard vs soft at a basic level, some prefer stiffer and Pirelli are soft (hence easy to puncture).
And as you seem to talk about ultimate grip being the no.1 factor...how many Pirelli's made the Podium at the TT? (Superstock)
The Power RS is a great tyre, I know, I have used them. I have also had good fun on an set of Rosso3's. I love the front end confidence from D212's, but have 2 sets of V02's waiting to go. RR K3's are a great tyre like the SC's, same factory...probably the same spec without the premium price. I am currently running around on Conti SA3's, last forever, no moments, I'm on the road not the track. Point is I actually try different tyres, profiles etc, to find what *I* like. I don't just decide that the company spending millions to promote via BSB, WSBK, F1 make the best tyres for me.
- Alex