Larry Summers and Janet Yellen are the two leading candidates to replace Ben Bernanke as Fed chairman when his term expires.   I favor Yellen.  Ezra Klein has a pretty good overview of the perceived strengths and weaknesses of each here.  Klein notes in his piece:

Liberal senators hold incredibly strong opinions on the controversial economist. They blame Summers for the financial deregulation of the 1990s, and even if they could forgive that, they resent his opposition in 2010 to the Volcker rule, a proposal in the Dodd-Frank reforms to restrict banks from using deposits to make proprietary trades. That he has taken a bunch of money from Wall Street in the interim doesn’t make them any happier.

Read the text of the Senate Democrats’ letter in support of Yellen here.  I think their basis for recommending her is solid.  Summers’ role in deregulation, opposition to the Volcker rule, and willingness to take $$$ from Wall Street are exactly why I’m not keen on him.  (Those things and this too.)  Ezra Klein with the case for Summers here.

Beyond assessing their qualifications for the job, Miles Kimball’s “Three big questions for Larry Summers, Janet Yellen, and anyone else who wants to head the Fed” are precisely that.  I’ll add a fourth question: “Mr.Summers/Ms.Yellen, would it be prudent to mint a multi-trillion dollar coin if Congress refuses to raise the debt ceiling?”