At RealClearPolitics, Bill Scher urges him not to run:

The question is: Would Biden’s reputation survive?
As it stands, Biden can take pride in one of the greatest legacies in American politics. During his 36-year Senate career, he shaped the Supreme Court, leading the 1987 fight to defeat the nomination Robert Bork, which eventually forced President Reagan to settle for the more moderate Anthony Kennedy. (Nearly 30 years later, Kennedy would rule that gays have a constitutional right to marry. Thanks, Joe!) In 1994, Biden drafted and shepherded the Violence Against Women Act to passage, a landmark law credited with contributing to a nearly two-thirds reduction in the number of domestic violence cases.
As vice president, Biden served as “sheriff” of the stimulus, successfully keeping the massive Keynesian influx of cash from succumbing to waste or fraud. He personally struck the bipartisan 2010 deal that temporarily extended the Bush tax cuts in exchange for crucial additional economic stimulus. (Without either stimulus effort, Obama would almost surely have been doomed to a single term.) Then after re-election was secured and the economy was on firmer footing, Biden sealed the bipartisan “fiscal cliff” deal that repealed the heart of the Bush tax cuts for the wealthy. He is one of the most influential vice presidents in history, without any of the waterboarding.
A brutal battle against a candidate poised to make history risks marring that legacy, particularly his achievements for equal rights. And it remains a battle he is more likely to lose than not.

Outside of the merits of these supposed accomplishments, how do any of them change if Biden runs and loses? Yes, he will be called a sexist a lot over the next six months, but even if he loses, vice president of the United States will still be the first line in his Wikipedia entry. And at this point, he’d be doing the party a favor by providing it a viable alternative to Hillary. She may not be truly melting down, but so far everything that has happened is certainly consistent with a meltdown. If Biden is up for it emotionally and he still wants to be president, opportunity beckons.