Wow, everyone seems to have terrible favorable ratings. Of course Hillary's 36% favorable, 55% unfavorable, while not the worse, are certainly the most significant. Her net favorable is now worse than even Trump, who is 35-53.
Biden (who isn't running, at least not yet), and Carson (who no one ever bothers attacking) are the only 2 candidates with a positive favorable rating.
Hasn't Sanders had a positive favorable rating in every other national poll?
He's been positive in most, and averages to +2.2 on Huffington Post. However, his -8 in this PPP is actually the best he's done in the 3 PPP polls. PPP just doesn't seem to like Sanders. Aside from PPP, he was negative in some Yougov polls, but the latest Yougov is positive, and was -1 in a couple of other polls months ago.