Fiend was an interesting premise: meth-heads survive the zombie apocalypse because they are meth-heads. But because they are meth-heads, they can't have their own society to remain safe because that fix, that desire, that hunger, for the next fix makes them just as selfish, mindless, and animalistic as the zombies.
I ended up not finishing the book, not really caring for the main character. Some of the first person descriptions were a little too graphic, done more for shock value than anything (such as the bloody zombie girl sitting on the couch like a used tampon), and detracted from the story. The lack of quotation marks throughout also made it difficult to follow if it was just the main character's internal monologue or actual dialogue between characters.
One thing that I did like was the zombies giggled. That made them all the creepier, especially when i thought of other zombie movies and shows like Walking Dead and Dawn of the Dead. How creepy would those undead have been if they walked around giggling all the time?
Sadly, while this was a new take on the overly bloated zombie market (much like the undead themselves), it wasn't that fresh or inventive... Much like the undead themselves.