Quotes from the news wire:
Biden will likely continue to take a page from Donald Trump in 2016. If you'll remember, Trump essentially, just treaded water in the debates, he never won any debate but he managed to stay above the fray. Biden is likely hoping that he can ride a similar strategy to get through a splintered Dem primary.
If you doubt that Democrats can defeat Donald Trump on a progressive agenda, then Biden is going to continue to have a pretty strong lead, but if you feel like Democrats need to go big and bold and push the envelope with a transformative new agenda, I think it's pretty clear where you are going - to the left flank of the party and choose from the Sanders/Warren wing.