The more and more I think about this thread the more and more I feel the need to say this.
No actor portrays batman the 'best'. The viewer is really the one who portrays batman. Your thoughts and beliefs portray batman, and decides on if one actor is the best choice for that person's own visuals of batman. Batman isn't the same to everyone. to some people he's a merciful hero, and to some people he is a cold hearted Beast, with a terrible past Who isn't afraid to take a life. What I'm trying to say is There is no definite batman, or for that matter there is no 'best' actor to play batman. But their are perfect actors to play the batman that one thinks is suitable to play his/her own thoughts of batman.
opinion-a personal belief or judgment that is not founded on proof or certainty.