I got this jacket last night. In terms of fabric, it is unbelievable. Whisper thin and very cool looking - I love it. However, I put it on and thought it was going to cut off the circulation to my arms! I am 5'9" and about 165 lbs. in pretty decent shape. Usually a medium fits great on me - I am not even a "big medium". The medium in this jacket was way way off - too small. It seems like MH puts all the emphasis on advancing the fabric and has great success there, but then screws up the pieces with their quirky sizing. I am going to try a large, but I am not confident that some other aspect of the sizing won't be off kilter. Other than the sizing issue, this is a nice piece of gear!