One anti-Obama meme that I notice has gotten a lot of support even among people sympathetic to his cause is the notion that he's somehow shallow or insufficiently well-versed in policy matters. Obviously, I can't crawl into either candidate's brain and take a look around, but this idea doesn't seem to me to be especially well-supported by the evidence. Instead, it seems to draw support from a kind of implicit Law of Conservation of Virtues -- the pretty girl can't be smart, the not-so-good-looking guy must be really nice -- that has people notice that Clinton is well-versed in policy but isn't a charismatic figure, and Obama is charismatic so it "must" be that he's not well-versed in policy. He's cool and she's the nerd.
This suits the media's taste for parallels and lazy narratives into which events can be squeezed. But there's really not much basis for it.
For one thing, these takes tend to have a certain vague quality to them and often are offered by people who don't, themselves, have a particular aptitude for policy. I've never heard an anecdote that involved someone talking to Obama about some policy question and walking away feeling he had a notably poor grasp of the issue. Those things do happen, though. I definitely had a conversation with a then-Senator about Iraq in 2006 in which I got the impression that though the Senator was working earnestly to inform himself about the issue his actual knowledge base was shockingly low considering how long the war had been going on. But with Obama? I haven't heard about it.
Meanwhile, this story is one of several narratives that seems to me to overlook his time in the Illinois State Senate. Obama didn't have some vast army of staffers to rely on in that role, and he wasn't just serving time there, either. He successfully authored and passed legislation and impressed a lot of Illinois progressives. Nor is the University of Chicago Law School in the habit of handing out teaching positions to dullards. Which brings to mind the additional point that one way the allegedly vast Clinton edge in policy expertise sometimes gets argued for seems to be defining "policy" in such a way as to make things where Obama clearly has more knowledge, interest, and experience -- constitutional law, criminal justice, non-proliferation policy -- not count as "policy." In the real world, appointing federal judges and prosecutors and weighing-in on federal litigation is an important presidential function.
Last there's the question of staff and advisors. The various smart people working with him on a whole variety of issues -- starting with Samantha Power and Karen Kornbluh when he first got to the Senate and expanding ever since -- don't have any really compelling reasons to have been working with him unless they thought he was a smart, impressive person who was up to the task of doing a good job on the issues they care the most about. Unlike dynasts like George W. Bush or Hillary Clinton or ex-veeps like George H.W. Bush or Al Gore, Obama hasn't had the luxury of simply inheriting a vast apparatus by default, he's had to build it himself. That's hard to do if experts come away from talking with you worried that you don't know what you're talking about.
UPDATE: On the conservation of virtues point, note that everyone agrees that Bill Clinton is both very well-versed in policy (like his wife) and a charismatic figure. There's no fundamental tension here.