I echo many comments from other reviewers. I absolutely love these shoes. Super light and comfortable. Unlike some others, I haven't had any durability issues with the upper and the bottom don't seem to have worn much after about 150 miles. The one complaint I have is that despite what seems like a snug fit, my foot slips forward on steep grade downhills, which for a longer runs, I have had a blister develop on the tip of my big toe. However, for less technical grades on any terrain, I love them!