Zombie apocalypse is a great concept, and well written. Instead of having core characters central to the plot, it pulls in emails, diaries, tweets, web pages, blogs and letters from a variety of characters (some recurring) to put together the UK (initially) then world reaction to a zombie plague.
The source of the plague itself is a little far-fetched, but original and seemingly well researched. You get to read of a character succumbing to the plague (a young girl) which is quite emotional. The pace is good, and the "material" pulls well together to form a good read... until the end.
There seems to me to suddenly be an abrupt end, or culling, or so it seems, and I am left wanting as to what happened, and why. You have no closure on how the plague was dealt with, where survivors are, and how mankind is doing (especially with the nonsensical letters from the possibly alive, possibly not, US President and UK monarch). Unless I *really* missed something. Or my printing of the book had pages missing!
Would liked to have seen it ended with more "grace". But for the masterful originality and the quality of the writing itself, it still gets 3 out of 5, and is worth a look if you've already ploughed through the other quality material in the genre.