I purchased a pair of these socks and liked them enough to buy a second pair. I had bought the lightweight socks last year and they were too thick for my liking so I gave them to my wife who really liked them. She used them when we were hiking in the rain in AK last summer. The ultra-lights are still thicker than I prefer for biking, running and hiking but they are thin enough that I can wear them in my shoes when it is super wet and cool. Quality construction, retail price is quite expensive so I purchased my two pair when they were on sale.
These are pricey, but I often find I have to wear double socks depending on the weather. With this, I can go with a single pair even in cool / wet weather and it's fine. They're pretty thick and can take a little more effort than "traditional" socks to put on. But once you get the hang of it, it's easy to do. Pair these with a good shoe cover (like the Pearl Izumi P.R.O. Barrier WxB Shoe Cover) and you're good down to 30's).
These feel more like "double socks" when you go to put them on. You can see / feel the multiple layers. I will say that I used them on a century ride in the low 50's and rainy. They worked great except I had on knickers and water ended up funneling rain inside of the socks. And they actually keep water in just as well as out. So I had to ring my socks out at a few of the scheduled stops since my feet were filling up with water and getting chilly. But that was more of a usage problem than a product issue. After ringing things out, my feet recovered fairly quickly and had no issues for the rest of the ride. If I had on different pants or had hidden them completely under my shoe covers, I probably wouldn't have had any issues.
I still highly recommend them. Pick them up on sale if you can and it takes a little sting out of the price. But I would gladly pay full retail to keep dry / warm on certain rides!