I was hesitant to order--these shirts are a little pricey for my budget. But I have not been disappointed. I am 5'8" and 130 pounds and sometimes wear small, sometimes medium. I ordered two bamboo shirts in small, but found them a bit more clingy than I like. (I'm nearly 40. The ol' stomach isn't as flat as it used to be.) I exchanged and ended up with one shirt in bamboo and one in hemp, both in medium. Love them both. Bamboo is much lighter weight and softer. The hemp is warmer/thicker, and will probably last longer. It doesn't breathe as well as the bamboo, of course, but both are great shirts. The most impressive part of my experience though was working with the ONNO customer rep when I need to make the exchange. I was extremely impressed with how helpful she was; no generic answers here. She gave me personalized advice and made sure I received my replacement shirts quickly. Then, when I asked how to return the first shirts, she advised me to donate them. *Mind blown.* With policies like that, ONNO is a company I will work with again. SUPER IMPRESSED.