"I guess I am the anally retentive Ghostbuster, after all"
Pretty accurate. Stiff and slow action with an attention to details that was uninteresting. Worldbuilding is a bit too easy. We have ghosts and other supernatural creatures but there is no impact on the landscape of London and the secondary characters.
Felix is not a particularly likeable character. The noir style quips and humor that make the Dresden Files a fun read is not present or poorly rendered. He seems to do his job without passion.
The writing style doesn't cross the ocean quite as well as other British authors. I can enjoy learning a bit more about British culture and history if it adds color to the story and British slang can be picked up jest as easily as frack'n made-up slang. Theat being said, when stuff like Rorke's drift is referenced theres an awkward pomposity introduced that makes the book a bit stiff.
After a moment or so, inspiration came.
“I’ve got this trench coat,” I told her. “One careful owner.”
Fast paced ending and decent hook at the end saves what was sometimes a tedious plot. Big magic is possible but lightly used. Felix is a bit of a lightweight but he puts himself at risk to save the day.
The twist at the end is a strong enough tease to get me to read the next book. I'm reminded of the unevenness of first bunch of books of the Nightside (Simon Green) series. Like the Nightside, I hope the Felix Castor series finds a unique identity and tone while steadily improving quality of writing.