Can't believe there hasn't been a review for this manga yet.
Anyway, I'm enjoying the heck out of this. I basically hate any and all vampire-type series (Twilight, Vampire Knight, whatever) but this manga barely has any romance and focuses mainly on action and plot, which is a big A+ from me (and the little romance present isn't bad). There's some interesting twists on the typical vamp stuff (no sparkling!) and the action moves at a pace fast enough to keep me on my toes.
Characters are also pretty awesome. The protagonist (Abel) has a front of being clueless and clumsy (which makes for comedic relief), but it's shown pretty quickly on that he's not all who he seems to be. Supporting characters also get a bit of their own background and aren't as black-and-white as they sometimes tend to be in other mangas. My only gripe is that Esther can be a little idealistic and trusting at times, and some villains are too "evil" to be realistic.
Art is great, storyline is great. Lots of interesting themes and political undertones and corruption and all that jazz. There's a lot to do with the Church as well, and issues of morality and values. It's just a really great series (with kick-ass costumes too) so I definitely recommend it if you're into dark gothic settings and sci-fi and lots of bloody battle scenes.