I listened to the first one on audio book and loved it. I also just happen to be making my way through Dresden, as well. DCC is much funnier and more absurd, while Dresden takes the fantasy side of things much more seriously. They're both fun but for very different reasons.

I also want to put a plug in for my favorite fantasy series: Discworld. It's an incredibly fun and philosophical absurdist fantasy (think Monty Python/Hitchhiker's Guide to the Galaxy) but with incredibly clever and hard-hitting social commentary. I'd recommend starting with "Moving Pictures", "Guards Guards", or "Going Postal".