"Rise up! Rise up and reap their flesh for the Lord of All that he might take pause and look upon us, his children, and be glorified!"
They both have merit, but I do like the longer weapon slightly more. I'd also suggest experimenting with the orientation of the longer weapon -- see if it looks better horizontal (pointing outward from the raptor's torso), or perhaps even pointing downward (like he's about to stab something on the ground)?
I like the longer weapon too, though jabberjabber has a good point that it might be better in a different pose. Right now it look as though he will have trouble moving because the pose emphasises how long the weapon is compared to the marine.Definitely better than the axe though :-)