Agree with extrememarine that tire discussion is quite subjective. I see also that PR2's & 3's seem to be chosen for longevity (not just on this forum). To add my data point on PR2's, they are not my tire of choice due to experiences I had. I had a new set at CFR in Mt. Tremblant, and they were great when pushed hard in the twisties in the hotter weather. I prefer a little grippier tire...... but when it gets down into the 40's and tires are half worn, the grip was not as good. Below 40, I wouldn't push them too hard as I had a couple of pucker moments when the rear slid out when leaned over. That's the time to lower the pressure a bit so the tires will stay warmed up better. If you never ride in those temps, then I think you're good to go with confidence. That said, I am interested in trying a PR3 rear, and I'm only going to speculate the formula is similar to the PR2, but the tread pattern may allow a wee bit more flex to work better when it's colder. Again, all a compromise of what one wants for grip and wear, and wet performance.
I like the Z6 front for grip and decent wear. I usually can get 8-9k out of these, and consider myself moderately aggressive. On the subjectivity part, I always wonder how some of you only get half or two thirds of that. I tried a Z8 front, it was OK until it was mostly worn, but the already sparse tread pattern isn't as good for wet performance as it wears, didn't quite last as long as Z6's......... Z6 fronts work for me and are quiet. Question, are the PR3 fronts noisier than others? i.e., that road noise that comes up through the forks in front of the tank? I might try one if you guys say it's quiet.
I never tried a Z8 rear, not a fan of the tread pattern, but will give it a go one day. Z6 rears start to cup and get noisy way too early, PR2's did for me too but later in life. Partly spoiled by the longevity of the Michelin Exalto, have been away from trying rear tires for a while now............ there is an opportunity here as the Exalto is now worn out after ~37k miles, and even though there's a brand new one sitting here..............
I try not to be influenced by price too much..... don't care if I have to pay a little extra for a good tire.