Everyone is making good points....I say kakashi is on only because he has less to work with...other than that Itachi because he has defeated jinchuriki, stopped Edo, and knows when to back down...his ability was praised by kakashi at an early age..
Kakashi(Because of his inferior advantages)
Itachi
Sasuke(recent and childhood feats, saved Naruto multiple times)
Obito
Kakashi(Because of his inferior advantages)
Itachi
Sasuke(recent and childhood feats, saved Naruto multiple times)
Obito