I thought this was a solid book- interesting plot (the Romeo/Juliet parallel story was obvious to me from the start but I confess that the Umberto twist surprised me) but I did not feel as though the characters were that well developed so I did not feel as invested in the book. Also I think because it was the third book that uses the device of current day/flashback to historical times to advance the plot (People of the Book (my favorite), Winter Sea), I felt it was a little tired. Of course, if I had read this book before the others, I suspect I would have felt it about the others. Still, glad I read it.

I know what you mean about the obvious thing, but some things that were thrown in, to make the twists, didn't make sense sometimes. For instance, why would Janet break into her sister's room and ride a motorcycle to terrorize her? I mean, really. That was a little overdone, for me. It was good entertainment and fun to read, but characters were (as Bloom says) not as developed as they could have been.
In the end, I would also call it a solid book and fun to read.