(1) This is book 6 in the main series and there are ancillary books as well. Don't start here.
(2) In addition to the universe of vampires-ghosts-ghouls-oh-my, the author and her protagonist are sincerely Xtian (or, at any rate, they quote scripture un-ironically).
Frost's books can be relied upon to supply pretty high quality sex and violence. As the series has progressed, her characters have developed intimacy other than sex-and-violence, which is a nice addition (and not just within dyads or between dyads). The theme in this book is Cat trying to be more optimistic, and it is developed effectively and sincerely and also, at times, hilariously (reasonably certain that's intentional and it worked well for me).
The main character, Cat (don't start with the feline nicknames of heroines in supernatural romance series. If you can't cope with that, you can't cope with everything that's going to come with those nicknames), was born a half-vampire (dad was a vamp, mom a human), and becomes a vampire partway into the series (I forget which entry and don't feel like tracking it down now -- you'll notice I'm relatively kind to authors for continuity errors? I work at it). Cat's uniqueness (she's the heroine, she has to be Special) is that she doesn't feed from humans; she feeds from other vampires. And what comes _with_ that is any special powers her source has -- temporarily. It allows Frost to play with a superpower per book (or so), without making Cat so powerful it's completely risible.
I'll keep reading.
I love pre-ordering on the kindle. I can just line up new entries in series I'm reading as I stumble across them and then they appear magically on my reader and I can quit reading whatever I'm currently obsessing about and have a good time for a couple hours. Pre-ordering paper copies was similar, but somehow this feels more ... magical. I'm sure I'll grow accustomed and take it for granted in another few years, and forget what it was like to live any other way.