This book hovers between a 3 and a 4 for me. I normally don't find fault with the occasional error in a Kindle book. Almost every book I've read on my Kindle has had small errors of some kind. This book made the same mistakes over and over again though (later was spelled latter and Linda and Lisa were interchanged - even though Linda wasn't introduced as a character until the last quarter of the book).
There was a lot of ... "strange-ness" for lack of a better word. One person with an invisible friends another hears voices all the time ... It was distracting from what was otherwise a compelling plot that seemed plausible on many levels.
I did want to find out what would happen. I liked that the characters had many dimensions to them (as in none were the expected cliche and they had depth and sometimes did unexpected things). Sometimes that went too far. The priest is renouncing his faith at one point and pointing to God soon thereafter - with no obvious transition.
I think this was a very creative book that was obviously well researched on the scientific front. I think it could have been even better than it was and I look forward to any books this author might write in the future.