I recently bought a pair of these, and have used them for speedwork, racing and a bit of easy running too. They are very light, comfortable and fast, but I was surprised to see just how much outsole wear had happened in 260km (160 miles). All of the wear is on the forefoot (I'm a midfoot / forefoot striker), with only minor abrasion on the outside edge of the heel. The forefoot looks like it will hold up for another 100km at best.
What have been other peoples' experiences with this shoe?
PS I see from an old thread (Dec 2010) that people had better durability from the Hyperspeed 4.