From flipping 72 ton scorpion tanks, to being able to drop the atmosphere and land on the surface of the planet alive and in relatively good condition is what spartans can and have done (without wearing armor).
Those saying Astartes are stronger or faster is merely an opinion, going by the books and the game which in that mythos is canon shows the spartans to be physically superior.
Saying warhammer plasma guns are superior is once again pure speculation, one could easily state that convenant technology eclipses anything that the imperium of man has shown so why not their plasma weapons as well.
Spartan armor and shields have shown to be able to withstand direct hits from hunter plasma cannons, a space marine isnt going to get through that easily by any means.
If anything it would be the spartans that are dancing circles around the astartes, while pulling their appendages off their bodies.
Last edited by Lux; 05-08-13 at 07:10 PM.