The note "this garment fits close to the body and runs small" sounded awesome, so I got an XS for the purpose of climbing. Unfortunately, the XS did not fit to my liking. I am 5'6'', 120lbs, and typically wear XS in most brands. The arms on this shirt were a little long, though manageable. The drop tail hem in back is great, but the front hem is too short. I don't like for my lower belly to be exposed every time I reach up for a climbing hold. The torso is baggy on me. A minor detail that bugs me (maybe I'm OCD) is that the collar front is asymmetric. You can kind of tell in the pictures, but I didn't really notice it until I wore it in front of a mirror. Zipping the pocket closed is a little annoying because you have to hold down the fabric around the zipper to prevent it from getting pulled. Otherwise, the PolarDry material would be great for exercising in cool temperatures. The pit ventilating material extends along the inner side of the arms and down the sides of the torso.