I've used swiftwick socks for the past 3 years almost exclusively. I searched and searched for the best running sock I could to avoid blisters while running. Probably tried 15 different socks before I discovered these, which was ridiculously expensive to figure out. I just needed something that wicked well to keep my feet dry, fit snuggly even after lots of use/washes, and something that had the right amount of slip inside my shoe to keep my feet from blistering.
After three years of high usage, I finally had one pair wear out. I also love these for cycling. I recommended these to one of my buddies to try for long distance hiking, and he also has fallen in love with them. I can't recommend them enough.