Echoes of the past*
We know Hillary Clinton's past. Indeed, we probably feel we know it better than she does. Barack Obama, on the other hand, is largely unknown to us (unless we've read his biographies, which we probably haven't).
That, I think, is the real difference between the two candidates. Not to say they don't campaign with very different styles or that their race/gender don't provide some unique perspective and possibilities. But Obama is a vessel in which we can add our hopes and dreams, whereas Clinton is self-contained - you either like what she brings or you don't.
She's Hollywood formula, a well-trod storyline with a predictable ending (which is why California backed her). He's indie, interesting and captivating with an ending not so easy to predict.
He absorbs your hopes and you hope it changes him. She reflects your hopes and you hope that you like what you see.
He's a puppy, sometimes clumsy but utterly charming and full of qualities that should make him a good dog. She's a dependable older dog, loyal and wise but with peculiarities and prone to bite.
On Saturday, three states decided they liked the puppy best. Today, Maine voters get their says. We'll see if it gets decided in Ohio or Philadelphia or, worse case, by "superdelegates".
*The Washington Post has a story today about the influence of superdelegates in a close race, and it serves as a reminder of just how influential Bill Clinton might be in getting his wife back into the White House.