I am apparently one of the few people who just do not see what all of the hype is about on this one. I was really excited to read this after all of the glowing reviews it got, but I was left extremely disappointed. I found the writing stilted and stuttering (hard to stutter in writing, but this book pulls it off), overly sentimental, and heavy-handed on the symbolism.
I also found the author's approach to the story to be just plain gimmicky. The first and foremost gimmick (also see heavyy-handed symbolism) is that the story is narrated by Death. Now, this might work in some books, but not this one. The choice of narrator adds absolutely nothing to the story; it is only a distraction to the reader, and it also encouraged the author to add trite observations about Death's perspective (for example, he doesn't carry a scythe, but likes the human image) that add nothing to the story. If Death here had been given developed personality or a unique perspective, then maybe (and even then it's a stretch) the choice of narrator would have worked. As it is, the story is told almost entirely as though by an omniscient narrator (is Death omniscient?) and we get absolutely nothing from the choice of Death to fill the role. It's a gimmick, and it falls flat.
The other gimmick I found most distracting (these are not the only two, but they are the most egregious) is the repeated use of little newsflash-type, bold and centered notes that appear periodically through the story to highlight some stupid point and add (in the author's mind) dramatic effect. These newsflashes, as I think of them, were irritating and served only to break up the natural narrative flow without adding anything significant. This is another example of the author hitting the reader over the head with his points, rather than trusting his own writing to get the message across. This is another ill-conceived and heavy-handed gimmick intended to correct for a poor narrative.
I think it is telling that while this book gets listed as teen fiction, Zusak actually wrote it for adults. For some reason, it got identified as being for teens when it got marketed in the U.S. (it was written in Australia). It seems to me that the explanation for this change is that the novel feels like it was written by a very immature author, and so the prose does not attain the quality one should expect of adult fiction.
I think good Holocaust stories need to be told, but the Book Thief fails at that endeavor. The story is trite; the narrative is sentimental and uninspired. I recommend that you look elsewhere for something better. If you want something for younger readers, try Number the Stars, by Lois Lowry. If you're a bit older, also read Night by Elie Weisel or the Diary of Anne Frank. I might even add in Fahrenheit 451 by Ray Bradbury, to counteract the heavy-handed book-burning theme of the Book Thief. There's plenty more out there that better deserve your time and attention than does this book.