This is another quick read/listen. But I did have some more issues with it. 
1. Everything was resolved a little too quickly/easily. 
2. The love triangle is a little ridiculous. One minute, he wants a relationship with Mallory, and then next, he is pining for Felicity. I still see the potential for a love square with Deputy Amy. 
3. He tells everyone the truth/everything so quickly. Dude, you just met this guy in a cemetery. You don't have to say to him you have an ancient artifact. 
4. Some of the terms are childish. Society of Shadow and the serial killer named Mr. Scary? Come on, be a little bit more creative. Also, the guy's last name is Harbinger. I see a lot of potential for him being a harbinger of death. 

That being said, I still liked it. 
1. It's quick, fast-paced, and straight to the point. There are no crazy back/side stories or build-ups that sometimes bog down a story. 
2. I love a handsome and sarcastic protagonist who wears flannel (umm, Dean Winchester)
3. It sets up a much larger and more exciting storyline

So, I will be continuing with the series for now.