I'm new to recent PNR so I've been trying out different authors to see what I like/can deal with. This was OK, much better than some others I've read recently. The writing was very good. I liked the warrior angel theme - those Biblical guys are actually pretty scary - and the philosophical elements of humans having to resist demons, not getting away with the "the devil made me do it" excuse. However, I would have expected Zacharel to know more about this than he apparently did. He's explaining this to Annabelle early on, she tells him she never learned this stuff (her parents were agnostic), but he never seems to understand why she reacts as she does. Of course, she forgives her brother (who was a complete idiot), but he doesn't get that his own brother made bad choices also - which he can be forgiven for, but who should also take on the responsibility of those choices. 
 Annabelle is much too young and strangely unaffected in weird ways by her experience. She was only 18 and still in high school in the prologue, spends 4 years dealing with the prison system for the criminally insane. Since Zacharel is a virgin (why, since the others are explicitly NOT?), she gets to have the sexual experience. So we have one lameo high school boyfriend, and one creeper, abusive Dr in the prison. This does not make for a good sexual background for them. Do we have to have rapey/abusive scenes in every "romance" these days? Wasn't the Dr nasty enough without that? And wouldn't true love and first time/pure sex have been so cool for this couple? 
 His decision at the end was completely understandable, but I would love for once to see the immortal make the choice to give that up for love. After all, we've got weird Greek myth vibes going on so why not go the Hercules (disney movie version) route?