I read vampire novels (you can see my reviews of dozens of them). I read Regency romances (and have reviewed a few). So you'd think that something that purports to be about a Regency-ish vampire hunter would be right up my alley, right? Well, it would be, if it were well done. But I'm picky about "well-done." I insist on at least the basics of characterization and plot, and a bit of historical accuracy in my historical romances, and dialogue that's witty. This book fails on all those counts.
It falls most seriously short on historical accuracy and period atmosphere. Some of that is deliberate; the author is trying so hard to get in sly puns and allusions to 20th-21st century pop culture that she deliberately stretches the way the characters talk. But other anachronisms are accidental and annoying - references to going to Plan B if Plan A doesn't work; references to someone's ego (I notice that one in many historical romances; people seem to space over the fact that we didn't start using that terminology until Freud laid it out at the turn of the 20th century...) Incidentally, the book is allegedly set in 1828, which is technically post-Regency, but not yet Victorian. There's a reference to Dr. Jekyll, even though Stevenson didn't write "The Strange Case of Dr. Jekyll and Mr. Hyde" until 1885. And so on.
Some of the plot devices were so predictable as to be passe - our heroine is carrying a flask of brandy and a vial of holy water in the same pocket; of COURSE she's going to accidentally throw the brandy instead of the holy water. (Let's never mind how our heroine has a liquor flask in the pocket of a light muslin gown; let's never mind that gowns of the period did not have pockets as we know them...)
And many of the allusions to pop culture were not worth making - the version of "Santa Claus is Coming to Town," for example, was (a) stupid; (b) not very well done as to imitating meter and rhyme, and (c) totally pointless with regard to the plot.
There are also the usual typos, grammatical errors, and word misusages that one finds in all too many mass market paperbacks these days; publishers don't seem to employ copy editors any longer.
To give the book its due, it's not totally unreadable. For a few pages, the allusions to pop culture are fun; if they came at about 1 every 10 pages, instead of being smushed together in run-on fashion, it would be a very funny style. I suspect that someone who isn't a dedicated Regency reader would be far less annoyed by the anachronisms than I am, and might therefore enjoy the book more. And if your only previous exposure to vampire fiction has been recent work that's more or less romance - Betsy the Vampire Queen, for instance - and has not included the serious authors such as Chelsea Quinn Yarbro, then you probably wouldn't be as bothered by the haphazard treatment of vampire powers and weaknesses, or the mixing of vampire and other supernatural cultures, as I am. So, if all you're looking for is a light read, not holding out for an actual good Regency or intense vampire experience, then this might be acceptable.