The first half of the book tells the story of Mortenson's dawning vocation in vivid, novelistic fashion. (In the third person, surprisingly, given that Mortenson is listed as the primary author.) It is a strong story about a guileless, naive, and somewhat passive protagonist learning about the difficulties of his chosen quest. Once he has completed the first school, the book takes on a more journalistic tone. It is a less strong story that paints Mortenson as a saint who gets things done. Everyone Mortenson meets, from US Congressmembers to Taliban leaders, declares him remarkable and donates to his cause.
I think Mortenson's life provides fantastic material for a finely shaded character study. This book opts for hagiography instead. He clearly has a magnetic personality that leads people to like him instantly. I suspect his clumsy naivete makes people want to care for him. I can't deny the success he has had, but I believe that the reasons for it are different from the reasons he believes they are.
I would be interested in a biography of Mortenson that explored his talents and faults in equal measure, and thought about how they work together to account for his successes and failures. I think there is a story along the lines of All the King's Men there. I sense some corruption and incompetence even through the positive spin. For example, after Mortenson's foundation gets a huge influx of cash, he uses it to provide a scholarship for one of his lieutenant's daughters. More generally, it seems like Mortenson uses his personal preferences to determine where money is spent, and he takes unnecessary risks to preserve his self-image.