While shes the one who's nearly identical to Obama policy-wise, Bernie has the energy and excitement Obama had in 08. Trump has it on the right, but he may have hit a ceiling. Cruz would be an easy W for any Dem. Even O'Malley could beat Cruz. Though I do think if Rubio pulls it out, he could be a problem for her

As for Bernie, I don't know what happens when the entire right wing attack machine is focused on him. Hillary is used to it. Though he's obviously doing miles better than many of us thought. The whole thing is pretty fascinating.