There were so many places Seanan McGuire could have taken this book. If Toby stopped running from place to place, driving like a maniac through traffic, maybe the author could have taken her there. And really Toby, it's time to invest in a cell phone. You've been back in the real world for a couple years now, there aren't any more excuses left. Really, some of your problems could be solved if you had a phone on you at all times.
The antagonist's motivations remain unclear. Seeing as it's the bad guy from the first book that we've been waiting to learn more about, it was a bit of a let down that we didn't really learn anything. This whole giving-answers-while-being-totally-vague-about-it thing that Ms. McGuire does is a bit annoying. For example, we get some answers about Toby's past and her mother, and about what happened to her liege lord's wife and daughter while Toby was a fish, but it's just raised more questions without really answering the original ones. If you're going to have a setup like that, readers expect a payoff somewhere not too far after.
I'm still reading this series wanting to get more answers, but I don't think they'll ever really come. And maybe it's just me, but the characters never react the way I think they should. Like the bad guy trying to kill an important character... Instead of chasing after her, the characters just settle down to watch another character die. It's a bit ridiculous. And does every antagonist's motivation HAVE to be that he or she is mad? That gets boring after awhile, too.