Let me start off by saying two things:
1. I loved the first installment of this series and couldn't wait for the second book to come out.
2. It took me 9 months to read this book.
It drives me crazy when an author is writing a trilogy and the middle book feels like just that- a middle book. For me, this installment just felt like one giant transition. Stiefvater's lyrical writing style became drawn out, predictable, and boring. By the end of the first chapter I knew what the final chapter would say. I desperately wanted a giant twist. Granted there was a small one at the end, it wasn't worth the giant book of blah it took me to get there.
The one redeeming quality of Linger was the character development of Isabelle. She really became a complex character who you could relate to and really began to root for. Grace and Sam started to really wear on me and I got the feeling if I knew them I would want to vomit from their sheer mushiness.
Grace developed Bella Swan syndrome in this novel. She said and felt things I don't think any seventeen year old girl would actually would feel. I think the whole girl with an old soul in a paranormal novel is a littler done right now.
I still love Steifvater's take on werewolf lore and the universe she has created. I haven't yet guessed how the series will end so I will definitely be reading the final installment. If you liked Shiver I would recommend pushing on through this book to make it to Forever.