First off, great shirt, stays dry, doesn't take on smell (even cigarette, seriously), and looks great. It also provides a fair amount of warmth for its light weight.
Now to the size: I'm 6'2", 170lbs and the large fits perfectly. The sleeve length is just enough for my longish arms and the hem comes right to the waist, which is perfect for a base layer.
A bit pricey, but worth it for me. When I first got the shirt I didn't take it off for like 3 or 4 days (and it still never smelled).
Do make sure you don't put it a dryer though. Just wash it normally and hang dry it.