** spoiler alert ** 
 It's pretty good compared to other YA novels out there. Like other reviews have said, the heroine is pretty good and realistic (except sometimes she loses her temper and stubbornly cling to the male hero). However, this book portrays it less stupid and deemed her loyalty as a tragic flaw). despite many eye-rolling moments between Penryn and Raffe's, their romance worked up just fine. I love the part describing their kiss, it was just perfect, it's somewhat sensual, beautiful but desperate and sad as well. 
 The mom really creeps me out here, but I guess that's a fresh thing to YA novel. I think the mom'a inner demon will come in helpful for the future plot. 
 About witty and sarcasm, this book is perfect. Actions done pretty good, the few last scene grossed me out too much! But I guess for a world as this, it is justifiable. The thing that really needs to expand here is the angel's political war and the cause of their invasion. 
 Overall, 3.25888768856 stars for me :)