I'm 6'3", 175lbs, the large size was a pretty good fit, had to stretch a bit because of my height. Medium would probably be way too small. The material was pretty good quality, I'll be able to wear it again, but the hands were rotated at kind of a funny angle relative to the arms, and the feet aren't printed all the way down to the actual feet of the costume. Also you basically can't see out of the mask, I painted my face instead (got compliments on doing that though). The groin flap thing is a nice feature, but since I'm tall it was like 5-6 inches too low and it was still a bit of a struggle to go to the bathroom (easier than taking the whole thing off though). The bones are glow in the dark, but you won't really notice unless it's really dark. Overall pretty happy though. Shipping was fast.