There are a number of things I don't like about Inkheart, so let's first get those out of the way. The sheer volume of swearing exasperates me; I hate those words buzzing around in my head, ready to pop out at the first annoyance. I'd like my children to learn more intelligent, or at least amusing, expressions for such occasions. (Personally, I like Winnie the Pooh's "Bother!") I dislike the ambiguity of the author's worldview regarding death, religion and the like, peeking through the story. I like real characters and not plaster saints, but I wish the protagonists were a bit more admirable.
Recommending Inkheart requires knowledge of the child who may read it. For example, almost continuous intense situations may fan the fears of a sensitive child. A child given to imitation may start saying "d-mn" and "Oh, God." (A parent could eliminate that problem by reading the book aloud, with judicious editing.)
Still, I cannot discount the tale for a mature child, solid in their faith. I like its imaginative premise and the creativity and skill with which it is written. The writing quality is good, if a bit lengthy and predictable at times. I'd love to see a really good editor work with this manuscript. Nonetheless, I can understand why Cornelia Funke is the third most popular writer in Germany (according to the book jacket).
The story raises some interesting discussion points, too. One theme, that "fear devours everything," is taught to Meggie by her father and provides worthy fodder for conversation. The following quote could open doors for discussion of the reasons people behave the ways they do and could ignite compassion for those who are unlikable, cynical and/or fearful: "Sometimes Dustfinger thought Basta's constant fear of curses and sudden disaster probably arose from his terror of the darkness within himself, which made him assume that the rest of the world must be exactly the same."
All in all, I don't think children will suffer great loss if Inkheart is left off their reading lists. For the child who loves the fantasy genre, can handle the pitfalls, knows about the book and wants to read it, and particularly for those who love to write, this story will be an enjoyable and creative excursion.