Whenever I teach a book where there's a movie version, I wonder whether my students are actually reading the book or just "taking the easy way out" by watching the film. I'm not certain this matters with Persepolis, which I happen to be teaching just as the movie version is released to theaters. For one thing, the book, a graphic novel, doesn't take very long to read (the film, and the most recent publication of the novel in the U.S., contains the entire batch of Persepolis books), so students might as well read the book. For another, the movie is actually a fairly accurate representation of the graphic novels, enough so that if you only see the movie, you've probably got the basic sense of the books (but don't tell my students).
The animation is appropriately sparse, drawing on the illustrations in the books, which were equally spare. Not to say ineffective ... the animation works quite well. But it works on pretty much the same level that the books' drawings work. It is neither an expansion nor a reduction of the art of Persepolis. The voice acting seems just fine, but since it is in French, I can't really tell how good a job they are doing. It's one thing to watch actors speaking in another tongue when we can see their faces ... when we only see drawings and we don't understand the words, it's almost impossible to evaluate the quality of the voice actors. And so, again, at least for non-French speakers, the movie complements the book, but doesn't really add or subtract much of import.
In short, Persepolis is a movie that will please fans of the book, which isn't always the case, of course. I am one of those fans, and so I think Persepolis would also please people who don't know the books. It is a strong coming-of-age story, perhaps a bit hurried in the film version but not overly so, with an illuminating historical background.
I would point out only one difference I found in the film compared to the book, that seemed important, although looking again at the book's drawings, I'm not positive I'm right about this. Without spoiling too much, there is a scene where the heroine identifies a man to the police as someone who is bothering her. In the book's drawings, as I see them, the man is just sitting in the background until the police roust him. Since the heroine only reports him to escape from her own police problems, her actions seem very self-centered, given that we can only imagine what will happen to the man. In the film version, the man very clearly gives the heroine a look before everything happens. Thus in the movie, what the heroine reports to the police really happens. Her actions are still cowardly, but they aren't reprehensible the way they seem in the book. A minor point, to be sure, but one I've been obsessing about.