As zombie fiction goes, Blackmore does a good enough job. There's not a ton of plot, but the characters eventually (by Book 3, at least) develop enough to be sympathetic. That's not to say they're very round. They aren't. Every character is little more than a stereotype of the genre, but the longer- lasting ones grow on you through sheer persistence.
Blackmore's writing is also good enough. Yes, he has pet phrases that recur enough to distract and yes, he occasionally uses a wrong word, but we're not talking about capital L literature here. He gets the job done and that's what we need in a zombie book.
Where I would criticize the books is in their staggering long-windedness. If Blackmore isn't getting paid by the word, he should renegotiate his contract. Dickens has nothing on this fellow. The beginning of the first book nearly put me off them all together. I've been a painter and the detail involved in establishing Gus's career still almost put me to sleep. I can't count the number of pages I skimmed in all three books collected here, just to get to something that actually moved the plot forward. Most of what I skimmed were fight scenes and zombie gore descriptions, no less. I like martial arts and fights as much as the next girl (ok, probably more), but holy elbow strike did these run on. If you took out all the superfluous detail from these three books, you'd have a single volume, but it would be quite good.
I don't suppose it's Blackmore's fault the zombie gore got tedious. There are only so many ways you can dispatch a walking corpse or be dispatched by one and they've all been covered ad nauseam by the scores of books, movies, and tv shows. My personal preference would be for a more matter-of-fact approach, but other fans of zombie lore may well like this part of the book just fine.
I would caution future readers that in addition to the usual zombie blood and guts, there's a fair bit of human-on-human torture porn mixed in. Not my thing, but that's just me.
There are two more books in this series. Despite my griping, I'll probably read them-- after I've had a break. Compared to the typical zombie novels available, these are above average. Blackstone is not Max Brooks, but I don't think he's trying to be. He's serving up a genre novel with all the elements most of the genre's fans want and he's succeeding. Do I wish he had a tougher editor (or just an editor at all)? Yeah, sure, you betcha. But he's doing what he set out to do and that's more than many of us can say.