I loved this book and don't understand why more people don't know about it. It's well-written, dark, snarky, and full of British humor. If you like Gaiman and Pratchett, you'll likely like this as well. Plus, there's a song about the Old Ones. What more do you need, really? 
 I listened to this via Audible and the narration is great (and they sing the song), but I'd probably recommend that you read it first and then listen or a mixture of both (this one has Whispersync, but the next in the series doesn't).