1 / the first, in substance: D.Allen recommends applying his method to all the tasks you have to do, whether in the professional field, staff ... everything! As well tell you that getting started is difficult ... And personally, I have come to ask me rather than making us time, this method "time management" we do not lose at want to force any sort, classify, organize and plan. There is (IMHO) of excess in the organization according to David Allen.
2 / The second reason relates to the form: the French translation could not eliminate a big flaw of the book, concerning the vocabulary used by the author. There sentences simply incomprehensible! "Vision", "collection", "stream", "job processing" ... it is difficult to link with his daily reality stupid.
3 / The third reason is on a more "philosophical" (a vision to 50,000 meters, looks like Allen): GTD privileges action, unlike Covey method that focuses on priorities, even losing in pure efficiency. Who is right? Getting lost in dreams materialize without them, it is the risk of the method of Covey. Drowning in action without knowing where we are going, what is the risk of GTD. Each method of "time management" seems to have its flaws ...
But finally, here is why this book deserves 4 stars in my opinion: GTD is simply very effective! If one is willing to make the effort to organize his life (which requires a lot of discipline), then the results are not made to wait. This is one of the success factors of the method elsewhere. Enjoy reading!