I cut and pasted the below info that I read on another hunting site.
In my unbiased, unscientific experiment during the last two days I had an opportunity to try both products that I recently received.
I had the most expensive warmest merino sock sold at Bass pro shop for under $ 20 vs heavy weight Alpaca socks at $32 that I bought at a Alpaca farm in Susquehanna county.
Both socks were very comfortable and not itchy. If I had to pick maybe a slight edge to the Alpaca
Warmth : yesterday I wore a thin liner sock with the merino wool socks with 400 grams in my Perfect hunter boots from Cabelas. Temperature was about 25 After about 1 1/2 hrs. My feet started to get cold but I lasted for another hour until it was too dark to shoot.
Today it was a high of 18 degrees and I used the the Alpaca socks and I was advised by the owner of the Alpaca farm not to were a liner sock. Again I lasted about 1 1/2 hours until my feet just started to get cold. I was wearing the same boots.
IMO maybe slightly I give the edge to the Alpaca socks. Maybe physically you get what you pay for.
However, if I was working for Consumer reports the Best Buy would go to the Merino socks.
I also had an opportunity to try my new Christmas gift of Minus 33 expedition weight long johns that cost an arm and a leg. They were very comfortable and not itchy at all. Yesterday with a high of 25 I never did get cold. Today with a high of 18 I got slightly cold But was able to stay on a tree stand until it got too dark to see thru my sights.
So out of all my cold weather long johns I would recommend the Minus 33. They are warmer then my Under armor cold gear and my high end Cabela brand underwear.