I'll admit that I'm a big fan of de Lint's work, especially the Newford stories, and especially especially ones with Jilly Coppercorn in them. So naturally--seeing as how this is a Jilly Coppercorn book--I loved this one.
This is the story of how Jill and Geordie finally get together (and how Jilly is finally healed from the tragic events of The Onion Girl and her own screwed up childhood). It's also a story about responsibility--almost all of the characters have something to learn about taking responsibilty for what they do and about not taking responsibility for what is done to them.
Besides that, it's also exciting. There's a war shaping up between the native Animal People and the Fairies. Unfortunately, this brings up the only problem I have with the book and much of de Lint's recent works. It's not a major problem, but I'll still mention it anyway. He has a need to constantly bring out the "big guns." Lately a lot of the action has focused on the super powerful spirit being like the Animal People and fairies, especially the uber powerful ones like Raven and the Crow Girls. It's not really a bad thing, but if you want a story where a person struggles against adversity, it's probably more realistic if they on't have a bunch of god-like beings as friends.
Still, this is a great book. I give Widdershins a full five yo-yos.