I've read Persepolis 1 and 2 as well, and I'd certainly recommend them. If you're thinking about it (which you seem to be), go ahead and read them. It won't take more than a couple of days to get through them.
The simple, hard images complement the tone of the book, which is chiefly interested in irony and contrast. A lot of that irony and contrast is shown through the different cultures, and Marji's understanding and comprehension of what's going on around her. A lot of power is generated with this approach, and it can go from humorous to devastating in a snap.
The emotion of her personal story and her family is a good balance to the harder elements that I mentioned above. As P suggested, it doesn't get sappy and sentimental, but rather lends an appropriate humanity that adds to the big picture.
Satrapi does a good job of portraying her own coming of age in a truthful way, not shying away from the embarrassment and confusion that we know all too well. And yup, I agree with P that Austria must've been one of the more idiocy-concentrated times in her life. Satrapi would probably agree with that, too.
It's a good book, though it felt a bit limited to be a great book. As I said, it takes about 2 or 3 days to read, and Satrapi can really only summarize and show the key moments of her adolesence. She chooses wisely which parts of her life to incorporate, and tells those stories well, but you don't (and maybe it's impossible in this form) get the full weight of a life that you can get with novels, in which you must spend much more time with the characters.
It's very much worth the time it takes to read, though, and is even, in some parts, eye-opening. I look forward to the movie.