Slightly misleading title.
Ultramarines are like the Roman empire.
Salamanders are like avatars of fire and molten rock - master black smiths that prioritise civilians over their own.
Space Wolves are unruly alcoholics that go apeshit and are likened to celtic warriors of old.
If you're asking 'who's the best' - well that isn't really fair as the Ultramarines are far larger than the combined military strength of both of the others put together.