Ambitious.  That was the first word that came to mind after it became clear where the story was going.  I love the setting, and the characters, and Holmes deserved her Agatha nomination for the first in this series, but as much as I admire her willingness to tackle such an intricate murder mystery, it didn't quite achieve success.  

The plot was a familiar one, but the method, while very clever, was too convoluted to feel as fresh as it should have.  I really like the angle she took with the murder method but by the end of book, I felt the same way I do after I've read an article on quantum physics: like I have the general idea down, but don't as me to explain it or it will all fall apart.  

I enjoyed a lot of the book, and I love reading about watch/clock making, so I'll read the next one, if there's a fourth, but reading murder mysteries should not feel like reading quantum physics.