I picked up a half-dozen of these socks when I saw them featured on Cool Material in Nov, 2014. After wearing them in the chilly, late-fall months, and with my first New England winter fast approaching, I bought six more pairs once they were back in stock. Best investment I made all year.
Lucas at ASCO tells me I've got more of these than anyone else (all bought at full retail, no shilling here, just a very happy customer). I figured I'd stop by and leave my thumb's up.
Yes, they're warm as hell, but breathe really well - no sweaty swam foot to speak of. I wouldn't hesitate to wear them well into the 50ºF range. They're thick, but pack out a bit and will make sloppy-fitting, oversized boots fit like a glove. Throw them on under an unlined leather boot, and boom - winter boot. In my thinsulate-lined Bean Boots, there's no amount of standing around in sub-zero temps that will leave me wishing for warmer feet.
The wool is top notch, doesn't retain odor, and stands up to weekly washing and drying with no special care. I know I probably shouldn't dry them, but I'm a US size 10, and prefer a snugger fit - they end up shrinking to just the right size for me.
I have no doubt these will last me well through the next few winters, but they do have a habit of walking away from me - girlfriends, camping buddies, all have taken a toll on my inventory ;) I'll definitely be back for more once the mercury starts dropping.