Here's what thought:
I really liked Schuyler. The other characters were pretty cliche--especially Mimi. For some reason, I expected Oliver to turn on Schuyler, and I was disappointed when he turned out to be pretty plain vanilla. I really didn't like Jack, which was sad, because I think I was supposed to.
The pacing was excellent, except for the ending, which was a blatant cliff-hanger. I hate that we never got a good explanation of what happened to Dylan. And because I hate that, I won't read the next one...although the time in Venice is tempting, because Melissa did a fabulous job with setting.
She knows New York, and it shows. She did a great job with the vibe and feel of the place and I'm curious if she was as good with Venice.
Also, I love the way she used the Puritan history and twisted it fit her story.
She had an interesting use of point of view (POV). In a writing class, I learned that every POV character needs a character arc--meaning that they need to grow and change by the end of the story. Melissa obviously didn't take that class. In fact, I'm not sure if any of her characters grew or changed. From my count there were 4 main POV characters: Schuyler, Bliss, Mimi, and Jack. But there could have been more, I'm not sure if we wandered into Cordelia's head or not. Melissa did a pretty good job of making it obvious whose head we were in--although a few times I thought we were in Melissa's POV and was shocked to learn we were following Bliss.
So, this book was meh for me, but not so much so that I won't read Isle of the Lost.