[sk546]

As others have already mentioned, the mid-range torque increase is the biggest plus point with the Polestar Optimisation making overtakes and joining motorways much better and safer. For me, these figures and the in-gear acceleration timings are the most telling improvements rather than the peak HP figures.
However, power and torque aside, the best improvements in day to day driving is the improvements in gear shifting that comes with the Polestar optimisation. The gear shifts are faster, smoother and there is less 'dithering' from the gearbox when you are pulling out from side roads or off roundabouts, massive improvements in that respect (in all drive modes, not just Power/Polestar Mode) and probably the main reason to get the software.

Most dealerships will allow you to get the software installed and try it for upto 14 days. If not fully happy with the improvements, they will switch back to the original software and give a full refund.
Best option is to give it a try and if you don't like it, get it removed.