For me, (although many people will disagree) the PP isn't a no brainer option. If you're driving at 10/10ths everywhere then yes, it's the one to go for, but I will be driving at 7-8/10ths max, and won't be pushing the car hard enough to see the benefits of the higher spec diff over the standard XDS diff. Furthermore, for me, only 10bhp extra wasn't enough to justify spending another £980. Had it been an extra 30bhp, then yes, it's a no brainer.
For me, no brainer options are Adaptive Chassis Control, Sat Nav and DSG.