There were some interesting points in the early stages of the book but I didn't necessarily agree with some of the conclusions that he came to at the end of the book.
I agree that we need to talk more about the deep, faith questioning phases of life and be more open to the fact that troubles do arise that can deeply shake our faith and force us to reexamine what we believe. I agree with his premise that dark things happen and that through that period there is the opportunity to enter into a deeper faith.
However, it felt like he almost romanticised this journey as one that all Christians should strive to go through in order to become a more rounded Christian, almost like a Christian who no longer needed the church or could no longer relate to Christians who had not gone through this stage (as if they had come to a place where they were above "pre-critical" Christians as he put it). I find myself in a very similar faith situation to the picture that he paints of the "chrysalis" but I don't see myself as being on some deep spiritual journey that will eventually lead me to being some form of higher Christian.
Rambled a bit but my main take away was that, going through hard stages in life that force us into a dark place where we no longer can see God should be seen as part of faith, not part of losing our faith. But, we should also not feel that we will eventually come to a place where we have to move on from our initial places of faith to find similar "post-critical" Christians who are the "real" Christians of faith.