"A book more about people than magic"
Even though this book has the trappings of fantasy fiction, the best gauge of whether or not you will like it has more to do with whether or not you like writers like Michael Chabon. In fact, I would go so far as to say that this novel is what would have happened if Chabon had written the Harry Potter series. Think of it as The Chronicles of Narnia mashed up with The Mysteries of Pittsburgh. Characters screw up, screw around, and generally flounder through messy, complicated lives. Heroes turn out to be losers; losers turn out to be heroes. The gains and losses of trust, love, and faith between the characters is far more important to this book than the details of a magical world.
Even so, the book does have a magical world, along with fantastic creatures and a well-crafted, driving plot. My only complaint along those lines is that the pace sometimes clipped along rather TOO quickly, especially at the beginning. Quentin's whole five-year academic career passes in under 100 pages; those readers looking for something like Harry Potter's quirkily detailed mundane-but-fantastical school days will be disappointed. This is a book about people, not magic.
This is not a book for children; neither is it for escapists. But that doesn't mean it is a depressing or mean-spirited book: the characters' revelations (like those of David Copperfield, Elizabeth Bennett, or T. S. Garp) are hard-won and compromised by the losses they endured to achieve them, but they are genuine revelations, and the book is overall a hopeful one.