[quote=@Necroes]
Physically, the only thing more impressive about a marine than an ogryn is their ability to survive in the long run. That's it.
[/quote]

Speed and stamina i'd say go to the marines.
Vision as well, muscle density, the ability to learn by eating. Depending on how you see it intelligence is a physical trait. The reaction time sure as heck is a physical trait.

I'd say Ogryns are only more impressive in raw strength. Sure ogryns can take a beating and are sturdy. But marines are more impressive in every other physical way.