This is by far the best shirt I have ever owned. I have worn it DAILY for the past three winters, for a total of approx. 600 days and it has only recently started to show signs of wear. This is also the warmest shirt I've ever worn. This is made of the best quality merino wool, much thicker and warmer than SmartWool shirts (though I do love their socks.) Now that I have found them on here I'm considering buying another for future use.
I have this and LOVE it. I wear it around the house, as a baselayer, and as an outer layer to the bar. I am 5'8" and 155lbs and the medium fits great for those uses. If I wanted a skin tight baselayer, it'd be a little loose but I do not. This thing is incredibly soft, warm, and good looking. I have since purchased a few more.