Bernie by default.
Pending any unexpected candidacy announcements, I will support Bernie in the primaries. His ideas are our ideas, even though thus far I see little reason for hope in his candidacy.
I might hesitate if I had any confidence whatsoever in Hillary's ability to win a general election, but I see how she operates and it's sickeningly defensive.
Every time I think she's learned something, she proves otherwise and does "that thing" again - putting out some press release belittling Obama because she once again believes she needs (or can possibly get) Republican approval.
It's also goddamn infuriating to me. In my view, Barack Obama is one of the best Presidents we've ever had - and I'm pretty certain that's how all history not written by Texas textbook committees will see it too. But Hillary doesn't get that. She doesn't see more than two millimeters in front of her face. That's why she voted for the Iraq War. It's why she does everything she does.
So the two main official candidates at the moment are this person who doesn't know how to lead, but refuses to follow or get out of the way, and whose perfect-world outcome is some razor-thin margin of victory with no mandate or coattails based entirely on the public rejecting the Republican rather than opting her way; and someone who does lead, consistently, at least in speeches, but probably is not (yet) adept at anything other than making good points - which, sadly, is only about 10% of politics even under the best of circumstances (the rest is image and knowing how to choose people).
I hope that Bernie Sanders takes the opportunity of his candidacy seriously enough to learn the other 90% of presidential politics, quickly, on the off chance that we choose wisely rather than (like 2004) failing due to fear of failing.
Still, I want more people running. It's not good for the health of the party to always be so certain of who's on the ticket.