I think this book has cemented my stray from Catholicism. The book is centered around “spiritual warfare”, a concept in itself I am saddened exists in Catholicism. This concept fans the flames of an “us versus them” mindset - one adopted by many extremist religion folks to brush off mental illness (which is done multiple times in this book). Should not religion be a complete beacon of hope, something to help you cope with the unexplainable evils of this world? I don’t have all the answers to questions like this, and I don’t think I found them in this book. 
I also found the stories themselves just outside the realm of believability. For example, it is my suspicion that the exorcisms that felt like hours were actually 10 minutes or so, and seemed longer in the moment and when looking back on them. A small nitpick I know, but one that popped up in every story.
That all being said, the stories are entertaining and the writing is personable, authentic and not over produced. I have no doubt Romero is a good hearted man, as are many Catholics who read this book, I just see it as doing more damage than good.