Elites have energy shields. Rechargeable energy shields. And, if we take anything from Halo Reach, Elites have some heightened healing factor compared to humans (remember their health regenerated slowly). Predators carry field med kits to patch themselves up nicely so they can continue the hunt. But their armor is much less advanced than Sangheili armor. Both races have plasma projectile weaponry, but only Elites have plasma swords. The Elites have vehicles in which they can bring into battle. I vote Elites.