The first half of the book is dedicated to proving that we really do live in an Age of Distraction, and how it's important to find focus in the midst of that. I don't much disagree with Babauta there, and I don't think anyone really does. Especially among the creative fields, people crave the sort of focused inspiration that he holds up as ideal.
But agreeing that this distraction is real and actually clearing some of it from your life are different matters. In section ii, clearing distractions, Babauta looks mainly at online distractions. But rather than saying 'Facebook is evil, Twitter is terrible, and Email will kill you and eat your liver,' Babauta goes up against the attitudes that make these services take up so much time in our lives. He urges us to unplug from the desire to always be connected, while at the same time recognizing that all of the services, used intentionally, have their benefits.
According to Babauta, we're hurting ourselves by paying attention to these distractions. So the last third of his book is about focusing, sitting down to finish a task and not moving or checking Facebook until we've done so. The third section of the book is how to focus once these distractions are cleared away. I found this part of the book very helpful: I'm applying a lot of what he talked about here in my own life.
The main thrust of Babauta's book is peace, when it comes down to it. He uses the word 'peace' 21 times according to my eReader. He frequently holds up his ideas as a way of finding peace of mind, and attaining inner peace. Unfortunately, he's got the cart before the horse. Simplicity and eliminating distractions can only come once we've gained inner peace. They're the result of peace, not the means.
Inner peace comes from a soul that is at peace. And there's no way to put your own soul at peace. Peace comes only through Christ. In John 14 Jesus says "my peace I give to you." With that peace as the centerpiece of our life, we can truly pursue simplicity and focus in our tasks, seeking to honor God and always keeping foremost that peace that we've received.
So there's a lot of good stuff in Babauta's book. I'm putting a lot of what he suggests into practice myself. But without a knowledge and understanding of true peace, the book is flawed. I recommend it if you're looking to simplify your life, but I recommend it conditionally: read carefully, and keep your filter on, and choose what you accept from the book (isn't that how one should read everything, anyways?). When you do that, you will find a lot of use and value in this book.