My first question when I finished this book was "How old is the Mr. Grahame-Smith, anyway?" While the merging of the original text and his writing is relatively smooth, there are too many adolescent double-entendres and a fascination with bodily functions usually reserved for kindergarten. I don't believe that you need either of those elements for a good zombie story, but if the author felt compelled to add them, I wish he had done so in a more mature manner.
Aside from those problems, Mr. Grahame-Smith does a good job retaining the feel of Austin's language and keeps the characters true to the original. What happens to Mr. Collins and Mr. Wickham is pure wish fulfillment for anyone who felt that those two individuals were not entitled to the semi-happy endings they received. Elizabeth, Jane, Mr. Darcy and Mr. Bingley are still the characters they were in the original novel, and the storyline remains the same. The illustrations are both gory and amusing and added to my enjoyment of the book.
Overall, I would not buy this book new, but it was a quick, fun read.