My thoughts:
There is a lot of pressure on Biden to pick an African American VP. Biden has known Susan Rice, worked with her and is comfortable with her. That is who I think he will pick. Her negatives: hasn't run for office before, will be a lightning rod for GOP to yell Benghazi & to stir up a lot of 'fake news'. Sen Harris has been the leader in many people's mind and may very well be picked, but I think she wants it way tooooo much. Would she be a faithful VP - waiting in the wings. :dunno
Since the VP pick could very well be called upon to step in and become president due to Uncle Joe's age, this VP pick is perhaps one of the most important in many election cycles - probably going back to Reagan when 'age was an issue' - even though Reagan made it an issue for Mondale (famous debate line of Reagan's that made Mondale laugh as well).
Who I want and who I think would be a better president among the VP candidates: Warren. While this is philosophically more left leaning than what I would want in a normal election cycle, this is not a normal election cycle. I think her grasp of policy and her understanding of the heart beat of where the USA is today would make her the president we need at this time if called upon. I think she has the compassion, passion, and experience and plans to lead successfully. I was leaning towards Sen Harris - but as I said before --I think she wants it toooo much.