As far as zombie apocalypse books goes, this isn't bad -- but I don't know if I'd say it's "good" either.
There's a lot of unnecessary scenes that don't really add anything to the story. A couple of the characters are interesting, but some are flat-out annoying.
The good thus far:
-- Action is described well, without becoming bogged down by military jargon or technicality.
-- Two or Three interesting characters thus far
-- E-Mail presentation ( in the beginning ) to describe the outbreak was interesting, even if only because I don't see it very often.
-- Typical zombie apocalypse. There's only SO much that can be done in one genre, especially THIS genre, but still.
-- Pacing. At times there's good action, or good characterization, everything is flowing well, then BLAM! Massive detour to pointless scenes.
-- Villains, aside from zombies, aren't believable. At all. They're just "Generic Bad Guy #1389711."
Current UNFINISHED rating: 2.5 / 5. So we'll see if the book picks up any.