I just received my Super Gravity Jacket and it fits perfect. I'm 5'11 200lbs (all muscle), I got a large and it fits like a glove. I think a medium would be too small as the waist is tight. I obviously haven't been able to test this outdoors yet (it's August), but just by looking at the material and fabrics, I think this baby will do wonders in a variety of weather conditions. From cool fall days to brisk winter, I think I have a winner! Go get one, it's worth it and throw out (donate) all your other jackets cause this one will cover most. Plus it looks damn sexy - so says my wife of course!