I don't know what Mozgus is capable of, but as most people seem to think it's between Scar and Anderson, I'll have to side with the latter.
Even with speed equalised, Anderson still outclasses Scar in durability, strength and skill. He can regenerate, he's strong enough to match Alucard physically (who can tear through vampires like paper) and, as Dream said, has deadly skill with his bayonets, which he has a seemingly endless supply of (explosive and regular).
Scar is more versatile thanks to alchemy, but I don't see that being enough to close the gap between them. Anderson should win at least 8/10.