It depends a bit on how the race unfolds, of course. As I've said from the beginning, Warren is the one closest to my own sensibilities, and the one I'd most like to see as president.

We need to get past thinking about platforms and issue positions. That's fools' gold. It seems like the "serious" way to evaluate the candidates, but given the current state of the presidency, all of the Democrats would have essentially the same terms. On health care, the best anyone can really hope for is to restore and mildly expand Obamacare (mildly expand in the extremely unlikely scenario that we win back the senate, and then make the dangerous move of killing the filibuster), which all of them would do. On immigration, all of them would restore DACA and push for broader immigration reform (and probably not pass anything permanent, but they'd do what they can with executive orders). On climate, well, none of them cares about climate, but they all say basically the same (usually irrelevant) things. All of them would appoint the same judges, because all of them would take advice from the same sources.

Electability is the ONLY thing that matters, it's the only thing that differs between these candidates on a level that would ever be practically relevant. Everything we've ever seen from the US general electorate tells me that Klobuchar would have a strong chance against Trump, Biden would if he doesn't find a way to fuck it up, and everybody else would be fighting from a position of significant weakness.