I voted PR2's as I've worn down two sets now and have been very happy with them. First set was replaced at around 21k km and was at the wear bars, second set is at 24k km I think and the tread has disappeared from the middle. That's on a FZ6 with a lot of touring but also a lot of stop and go commuting with hard acceleration. Will go for PR3's as soon as I find a set in stock for cheap, probably from motorcycle-superstore shipped to Niagara Falls. The back was super sketchy commuting to work yesterday morning, around 10C and a greasy wet road equaled tire spin accelerating from a stop and shifting into second for the first ten minutes.
I ran a set of Pirelli Diablo Strada's (same as a Metzler Z6 for what it's worth) before the two sets of Michelins and they were good too, survived over 20k km, but the Michelin's inspire much more confidence, especially in wet weather. I do miss the lightning quick turn in from the Pirelli's though