I have run Z6's front and back for most of my miles on the 1300. I got a set of PR3's 2 seasons ago and was very pleased with handling, although mileage suffered a bit. Last year I tried to order the PR4GT's and like many, could not get a front tire in the spring. I finally went back to the Z6's as I had a long vacation ride coming up. I have 11,500 on them and am very happy, as I have always liked the way they handle. I picked up a pair of PR4GT's in the fall and they are in the garage waiting to go on sometime this winter. I probly won't put any miles on till at least mid-Feb as we will have ice on the road till about then, but I am looking forward to riding them this next season.
Some great reports on here, especially helpful are the photos and info re: riding style and surfaces. I am a firm believer in air pressure as the primary determiner of wear. I keep mine at 42/42 consistently. The more anal I have become, the more mileage I have gotten out of a set. I also acknowledge the challenge of "chip seal" roads in the western states. We have alot of them in WA state, especially in the northern half as the weather is hard on the roads, and the hiway depts tend to chip seal every few years to maintain the road surfaces.
Thanks to all for your reports, as I have been eager to get the "low down."