This was the first "Erast Fandorin" novel I've read. I own another but haven't begun it (nor can I remember the title at the moment) and probably won't for some time. The protagonist is a turn of the century Russian government functionary who is part Sherlock Holmes (keen powers of observation and induction) and part Jackie Chan character (martial arts). The plot is a fairly complex labyrinth of dark, dangerous, dead ends punctuated by discoveries that illuminate new questions. The writing style is fluid and fun.
One reason it took so long for me to finish was this: After the first 100 pages or so, when I had become interested in Fandorin and his ways and with the exposition of the murder at the heart of the story, a new section begins in a place and time fully divorced from the action and with none of the characters from the first part. I'm not saying that this is a flaw in the novel -- I just found it off putting. After a time, I became interested in the new characters and was intrigued as to how this section would intersect with the first.
All in all a fun read.