I don't think either have a chance this cycle.
Last time I think Warren had a real chance to unseat Clinton. As much as I like Bernie, I think he only had a chance last time because all the main contenders dropped out early, or never got in the race in deference to Hillary, and her fundraising.
I think Bernie is still in the feeling out stage - I am still on hi mailing list, and the messages seem to be about gauging support - specifically financial support. With a larger field, the grassroots fund raising will be more difficult.