I love Lisa Shearin's other series, so I had to check this one out. I have to say that it is not what I expected, but not being what I expected is a good thing, because Mac is definitely not Raine 2.0. Unlike Shearin's other series, this story is much more dense, and therefore requires a bit more concentration to read. I loved Shearin's one-liners in her other series, and The Grendel Affair has a similar sense of humor, but there is less of it. 
 The characters are fun, and the mystery is interesting, I love the world that was created and the spin on the Beowulf legend. I will say that the end felt a bit rushed, particularly in contrast to the middle of the book which was a lot slower, but I feel like that may go away in the next installment because the author won't have to do quite as much explaining about SPI. 
 The story is interesting for urban fantasy because Mac has a job with SPI, an organization that polices the supernatural forces in New York, but she is new and she doesn't have any training relating to actually being in the field, which means she is often clumsy and makes a lot of mistakes. This was explained away by Mac's position traditionally not needed said training, and it was nice to have a protagonist who didn't know how to be the perfect fighter from book 1 - Mac has a lot to learn, and her drive to succeed and learn how to defend herself makes her more relatable. 
 I love Shearin's books because each one has a complete beginning, middle, and end - so I didn't end the book feeling as though I was missing something huge, I am just looking forward to what the author comes up with next.