Nice, how'd you size?
I'm 6'3 but really skinny so I got a medium, the sleeves are perfect length and the jacket is slightly too short but I'd have that any day over sleeves that are too short. Loads of room to layer underneath aswell man, if you copped you made a good choice.
6'3 and you can wear a medium jacket? Does it look like you borrowed your little brothers coat? I would like to see a fit pic of that.
I can understand maybe a medium for a shirt.. but jackets you usually size up. I'm 6'2, 180 and I wear XL for jackets.