Love them! These socks are tougher than I am on the trails! Just finished a difficult Ultra, and my socks worked great. No blisters, miraculously, and they stayed comfortable throughout the race. I did have a slight amount of bunching up at the toes later in the race, but only towards the end and that probably had more to do with my shoes, the amount of vertical climbs using ropes and me on my heels a lot getting up the hilly elevations. I have worn these on other runs of the same distance, and didnt have issues at all. I now own several pairs, and couldn't be happier. I have washed them so many times, and they are holding up great so far. I tried one pair a few months ago on a whim, and now own several pair. I won't use antyihng else.