I give it 4.5 - really enjoyed reading it. Good start to a series (not a standalone, at least the next one is out this Fall, not a year from now). Not a cliffhanger per se, but a lot left unresolved. 
 Basically, due to skyrocketing oil/energy costs, society has collapsed, cities have gone bankrupt. And there's demons. And apparently no coffee (a sure sign of Hell on earth, but at least there is still chocolate, I suppose a sign that there is still hope). 
 Riley is the daughter of a master demon trapper and the only girl apprentice. Her dad really doesn't want her in the family business, but she doesn't want to do anything else. And she's good at it. Then her dad is killed and every plan, every thought she had for the future is changed. 
 Different from most YA, this one alternates POV between Riley (who is still more the focus of the sotry and has the most "air time") and Beck, a 22 year old trapper who was her dad's right-hand man. While technically he is a "young adult" he has also seen a lot (a war veteran, a journeyman trapper). I liked getting his side of things, his perspective on what was going on. 
 I could go on about all of the characters and what happens to them, but I won't. The best part about Riley is that she breaks down, but she also builds herself back up. She's furious with Beck,because he survived but her dad didn't, but she tries to mend that relationship. She's apprenticed to a cruel master who hates her family, but she doesn't let him beat her down. She's dealt with a lot and survived, and remained a decent person. 
 There's some romance, but it doesn't overwhelm the book. 
 I would put this one at a bit darker and more violent, but it was tempered with some lighter moments, so it still felt balanced. There were creepy necromancers, scary demons that control the elements, others that attack anything, down to the annoying nuisances and the downight cute (really, who wouldn't want a Magpie?). There was this undercurrent of maintaining balance, the difference between the overzealous destroy all Hellspawn, and the "well, these little guys really aren't that bad." It will be interesting to see where this goes in future books.