First, I should say that I have played and thoroughly enjoyed Fable III. Despite that, I don't think that this book really had much of anything to do with the game, so that didn't really affect my enjoyment of this book.
No one is going to confuse this book with fine literature. There are many predictable plot points, and the character's personalities aren't exactly unique. Despite these failings, it was a very enjoyable read. I think it is perfect for what it is and most video game novels won't try to get much deeper than this one does.