Have had these for a couple of years and like them. Durable with none of my socks getting wear spots at the heels. Nice and soft, a very nice feel. They have reinforcement in the usual places and across the instep.
I use these in my lighter hiking boots and the expedition weight in my heavier boots.
These are comparable in quality and comfort to Smartwools and are a little cheaper! I bought several pairs last year and have worn them many times. Time will tell if they hold up as long as Smartwools do.
I bought these based on a friend's recommendation who was stationed at Fort Drum, NY. He used them in the winter there and in the summer here in Louisiana. Excellent comfort and temperature range. Better and less expensive than Smartwools. I wore the in very sloppy conditions on the Northside of Mt. Hood with zero problems. For spring and summer climbing I can think of no better sock. If I am going high altitude or deep winter trekking/climbing I may consider going with the heavier Expedition socks. But for 95% of what I do, these are the best socks available, hands down.
I have now switched to REI and Smartwool socks exclusively. Nothing else is as comfortable and performs as well as these puppies. I like the Smartwool a little more. They just seem more soft and cushy than the REI socks. The REI socks do just as good a job at managing moisture and preventing blisters though. I have a couple pairs of the medium and expedition weight REI socks. They get the job done.