I think both Kirk and Sisko are too driven by emotions and prone to bouts of hysteria to be considered superior captains. Sisko, however, seemed a little better at asserting his authority, exerting an intimidating/commanding presence, and dealing with a lot of problems between different people. Picard was just more classy, restrained, believable as an authority figure, and like I said in another thread, DISCIPLINED which I think gives him the edge in assessing who was a more ideal captain.