Have had a pair of FiveFingers for many moons. In fact, I was one of the early people to use them. At least in Hawaii. It is old, beat up and coming apart. My newish pair. It has a more aggressive tread for trail, but is not as comfortable as the original, which is slippery on muddy and wet trail surfaces, like rocks and logs. And you feel every rock and root. The new one also is thicker and rocks and roots are less likely to make you feel them as much.