Where to start?
When I first started this I thought it was inspired by Holmes and Watson. There were, after all, several similarities - a doctor and detective duo, period piece set in England (though this is Victorian and they were Edwardian), and notable chemistry between the protagonists. However, as I continued reading I stopped thinking that. The characters, cliched backstory notwithstanding, are their own people. They do not mirror H and W in any other way.
Right away I liked the setting and atmosphere. Felix Carswell, the doctor, was likable immediately. The way his past was intentionally shadowed felt frustrating rather than sparking my interest, but thankfully I didn't have to wait too long for it to be explained. Despite the wait, I felt it made his character more character more interesting.
His counterpart, Chief Constable Giles, on the hand, was instantly revealed as cliched, which dropped my estimation of him and the book as a whole. I also had a hard time swallowing his "murder board" tool to solve the crime. It seemed too anachronistic.
At first, the seduction of V by H made me roll my eyes, but as the story progressed I saw it was not included for gratuity's sake, and I could appreciate it for the plot twistiness of it. All things considered, it was fairly tasteful, if a bit more detailed than strictly necessary. (The similar scene with C was much the same.)
As with murder mysteries everywhere, it was fairly predictable. What I enjoyed were the characters and setting.