I like Butler mostly because he is not famous or has been talked about to death like Owen, Craig and McMahon. That means Bond films every 2 years again instead of the longer spread that Owen would probably require. He wants the role badly and he would not be doing other films inbetween to the extent Owen would. If EON wants their man to be Bond and Bond only then Butler is the man. I would prefer him to Owen at this point butthere is a better choice. Craig is too 'different' and looks much older than he is which I think has to be a factor.
He does not want to be type cast and would pursue many other projects during his Bond tenure. Owen is simply too old now and is difficult to deal with in negotiations, similar to Connery.
They are both solid actors and could pull it off easily. Let me say that I really like Clive Owen and Daniel Craig very much.