I don't necessarily think PE's are more durable. They definitely use better materials, or at least, are built better (they're a custom shoe after all), but I see PEs as built strictly for performance and don't need the durability that the GRs have... they don't need to last months or even years cuz if you get PEs, chances are, you're wearing new pairs every few matches. I see them like racecars... they are there strictly for performance and just need to last the race distance... and don't need to last hundreds and thousands of miles like commercial cars do.
I remember seeing pics of Fed's PE's and the toebox material looked very different. On the GRs, the Vapors had some Drag-on rubber (or whatever it's called), while on Fed's, it looked like a much thinner and lighter material. And also fascinating that trusty ol Phylon and Air Max was good enough for Rafa!
