First off, this book was very enjoyably quick read--it took me all of two days to finish it. The take on angels/demons was very refreshing and i like how it was able to explain their existence without bringing God into it, so even nonreligious people would enjoy the book. The opening chapter was full of incredible imagery, and the first few chapters as well were full of mystery and made me want to keep reading. there was also no clear line dividing evil and good on both sides, which was very refreshing.
However, though the plot was very original and interesting, the characters sort of got on my nerves. I get that Taylor is supposed to be a sort of angry person most of the time, but her personality just wasn't consistent, and it sort of bugged me. in one instance, she says that she's flying to the battlefield with a guy she barely knows, but they claim they love each other and have for at least 4 months...doesn't add up. Same with Gabriel. I think he was supposed to be portrayed as conflicted with his feelings for Taylor and his loyalty to the Council, but to me, he came off as too wishy-washy and indecisive. Chris, however, was brilliantly written, and i liked how his personality stayed consistent.
Still, some things just didn't seem realistic. i know its a fantasy novel, but honestly, if my boyfriend told me that he was an angel, i wouldn't immediately be all cool and ask to fly with him--i would refuse to believe it, and even after he proved it, still be wary for a while. any normal person would. i understand that Taylor was supposed to be "special" but she's still a person, and that just didn't line up. Same with Sam, as well. Her absolute willingness to just leave in the dead of the night with a guy who claimed to be a demon kind of made me mad at her. any sane person would have called security, and get Chris examined. in addition, the declaration of love between them just didn't make sense. i know that the'd been together, but there was nothing to suggest that they were anywhere near anything serious.
that's really my only concern was the characters. the plot and the concept of the war were incredibly cool (except for the fact that they had scheduled battles--sounds more like a peace than a war). and the ending was a great cliffhanger to leave off at. overall, it was enjoyable. out of hope that it will get better as the trilogy goes on, i may read the second one.