Smartwool was my choice for years, but recently noticed a big decline in quality; shrinkage and durability.
Two years ago I started wearing Darn Tough and I will never buy any other brand. The comfort level, breathability and durability are second to none. Plus, they have a lifetime warranty for those who feel that socks should last more than 3 years.
Darn Tough sounds good. I think I will give them a whirl. I noticed a dip in Smartwool quality as well a couple years ago, but my last couple pairs have been like they were in the good ol' days.