It's not awful but it's not great either. When I read it I was one young person who had walked away from church, not from God just church-as-we-know-it. One key element when I got to the book was glaringly missing. Why I left and what I felt why it was not worth my time going back. The kinds of churches I had grown up in and was attending loved God and the bible they had just forgotten the core heart of the gospel. God loves/loved us so much He took on human form to come and suffer to death for the love of us. For all the churches I had been around God was a stern judge-king, holy and untouchable, the gospel was something you used to get the lost through the Jesus door and Jesus was a moralizing teachers giving sermons bout being good obedient children. it was not until I stood on the verge of walking away from God as well as the church that I found the truth. The gospel isn't the tactic you use to get the lost saved and on the road of strict obedience, keeping score of good deeds and paying penance for the bad ones. The gospel is while we were yet sinners Christ died for us and once we put our faith I Him we are fully adopted by the Father and God the Father is not a child abuser trading His love for the rites and habits of "holy" Christian living.
Sorry for the sermon but I have heard my story repeated many times over by those who left church, some leave the faith totally, others leave the trappings called church. Sadly the author and the survey-research do not know this vital aspect of church leaving.