Best base layer I’ve ever bought.. Very happy with it. Used it recently to go snowboarding and it felt great; light and comfortable. I used it under a light running windbreaker and it worked great. I was warm and dry the entire time. Temp at the mountain was between 15F and 40F, and at times, under the sun, I even opened the wind breaker and base layer zipper to cool down.. can’t wait to teste it in colder weather.
I am 6”1’, 205lb, and the size L fit perfectly, not too tight and not too loose. It’s not too thick or puffy, so no trouble wearing sporty fit wind breaking layers  on top.