This entire series has been quirky and fun. Fast paced and humorous. Sometimes serious. It started out light-hearted, and slowly but surely has gotten more and more complex. Butcher did a great job of drawing one in, and has done a great job of incorporating past stories and characters into new and bigger story arcs.
This book was awesome about bringing in not just the major story arc that has been taking place over several books, but little bits and pieces that didn't seem to have any major impact in past books. Not a whole lot of series can say that they haven't degraded over the course of 11 books, but this one may have actually gotten better, if you're into big, deep arcs (if you like the fluffy fun of the first few books, that is most definitely gone). Fortunately there are still fun quirks through the book, so the story still has the same definite flavor the Dresden Files has had since the beginning.
Also +stars for Listens-to-Wind's fight with the skinwalker, and Mouse, 'cause Mouse is just awesome.
And as a total aside, I want to have James Masters's storytelling babies. He is a phenomenal reader.