[quote][b]Posted by:[/b] m3andak It depends. Neither of them are real, so we have no clue how well they are actually trained and how they would fight each other. Either one could win...[/quote] Speaking hypothetically though, judging on background universe material, Space Marines have the upper hand. They've had much longer to develop the bioengineering and weaponry utilised as standard equipment by Space Marines. I'd also go so far as to say that Space Marines endure much more rigorous training, mental and physical. [Edited on 01.28.2011 3:39 PM PST]