In early years (Precursors, Forerunners, The Republic) Halo wins. The Republic may have all its fancy smancy jedi, but those get killed by factory made robots. The Forerunners play with stars and make planets. In later years (human-Covenant war, The Empire) Halo wins again. Sure, Star Wars has its Stormtroopers and Rebels, but they can't compete in space battles. Star Wars fires lasers. Halo fires nukes, MAC rounds, Antimatter, and well, bigger lasers. They may do better on the ground, but Halo has Spartans and personal shields. And Death Star? Couldn't handle some Rebels. A full military assault by either Halo faction would ruin it. And that's not even considering the Flood.