Jonathan Chait gives her a better chance than most:
But while Bachmann may be even crazier than Palin on questions of public policy, she seems to manage to hold things together as a candidate. She can answer questions from the news media. She is putting together a professional campaign rather than relying on amateur advisors. She takes care to point out frequently that she is a former tax lawyer, and she does not engage in Palin’s visceral anti-intellectualism, giving herself the aura of a plausible president, at least in the minds of Republican voters. Bachmann may well combine Palin’s most powerful traits without her crippling organizational failures.
It’s worth keeping in mind that the 2010 election cycle featured a long series of conservative upstarts shocking the mainstream media by knocking off establishment-approved candidates in nominating contests. Obviously, the nominating contest is a series of state-level nominating primaries generally dominated by an activist base. Right now, the right wing of the party nominating field is a vacuum. Somebody is going to fill that vacuum.
Palin has partial executive experience (commented on here) while Bachmann has established herself as a stateswoman. I personally wouldn’t vote for either in the unlikely scenario that they were the last two standing for the GOP nomination. I do like that Chait gives Bachmann the fair credit due to her while still not brushing under the rug her craziness.