It just seems like Obama is truer. He is acting out who he is, doing only what he could do. I see Hillary as more calculating, with her message vacillating from guns to trade to whatever the flavor of the moment might be, and without a core centrality that connects it all.
I read Obama's Dreams From My Father. From it, and watching him, listening to him campaign, I see him as someone from a diverse, poor background, who has truly wrestled with questions of race and unity. In Chicago, before law school, he organized a dispirited and economically-depressed neighborhood, brought it together, and inspired them to win basic services from the city (that had been neglected). Now, when pressed by the 'gay press', for example, on why he doesn't do more interviews with them - he responded that he gets the same criticism from the black press and from many other 'niche' group pressi. He responded that he doesn't want to put constituencies in boxes, separate them, and give each a separate message prepared especially for them. He wants to reach the whole audience, with one message, and bring them together. I see this coloring of unity and organizing all about him.
He also seems to have an ability to pick out the neglected cracks, the empty spaces between boxes, to say what needs to be said. Listening to his speech in Philadelphia I felt he spoke in such a way that the mere words themselves were healing.
I think he has a message that is so integral to who he is and so tightly connected with itself that attacks on him are beaten off almost automatically. The 'bitter' controversy, with its so immediate attacks by Clinton and McCain, seems to have glanced off him like nerf balls. Because, because because because, he speaks the Truth and he means it.
This is a late night confused post but it seemed like a good idea.