Good stuff: 
 - the storyline is unique, a breath of fresh air compared to a usual ghost story 
 - vivid imagery, R. Riggs is really good with describing places and making it actually feel creepy (this coming from a person who hates reading long descriptive passages and usually skips them) 
 - interesting characters and unexpected plot twists 
 Not so good: 
 - quite slow-paced: although it was an interesting read, but at times I kept wondering when is something important going happen? 
 - not enough drama for one to wonder what's going to happen in the next book (I did buy it, but can't say that I can't wait to read it), can't say that R. Riggs made me care about any particular character in the book 
 To summarize: the book is... fine, but nothing special.