Gin, or The Spider, is a bad-ss chick killing the unfortunate people that crosses her path and humps the (few) ones that she does not kill with the same enthusiasm. The descriptions of said activities are in no way over the top but they are indeed graphical enough for me to feel that this is more of an adult book. 
 Since I have relatively recently read the first two books in the Mercy Thompson series it is difficult for me not to compare them. Both have the same basic setting, girl with magic powers in urban fantasy setting goes on adventures. That is pretty much where the similarities ends though. Mercy wallows in her own perceived misery, she is week and always the underdog and the books are quite slow to get anywhere. Gin is really Mercy's opposite. Gin is a I-do-not-take-any-bs chick that frequently solves her issues by eliminating the people causing them from the equation. 
 The book is good enough written. It advances the story at a decent pace. The story itself is perhaps not the most brilliant or original one that I have read but there is nothing really wrong with it and it serves as a decent enough reason for some action. The background environment is not at all as detailed and developed in this book as in the Mercy Thompson series though. Vampires, dwarfs, giants are there but mostly they just act as any other person. The fact that they are vampires, dwarfs and giants is almost just glossed over. 
 Bottom line is that I enjoyed this book quite a lot. I enjoyed it quite a bit more than the Mercy Thompson books primarily because of the more straightforward action and kick--ss main character.