This book is part-history, part-self-help/motivational, part-adventure. It tends to blur the line a bit between history and non-fiction novel
The good thing about reading a history book like this is that it is nowhere near as boring as a text book from a history class in grade school or college. It's a quick read, you'll learn some new things, and you'll retain more because it is a chronological narrative (i.e., the connections from one point to another are easily made and kept in your mind).
The bad thing is: it's a quick read. Since you'll be done reading it quickly, you'll feel like stuff has been left out (something, perhaps, that your history teacher would have gone on about for days but would have bored you stiff).
It should also be noted that this is not, strictly speaking, a history book or straight biography. As I said before, it is part motivational reading. Every other chapter is Glenn's interpretation of what you just read in the previous chapter and how it relates to our times and to the person reading the book (i.e., "lessons to learn from this"). Even if you agree with Beck, it can make the book feel, at times, like an after-school special or a "one to grow on" PSA in the middle of Saturday morning cartoons.
That said, it'll whet your appetite to learn more about Washington, the founding of our country, and the people involved - much like when you first meet someone and start dating them to get to know them better. However, I imagine most of the other books about Washington (or history in general) may seem even more dry and boring than before - kinda like wanting to know more about your dream girl just to discover that her family and friends are the most lame people in Dullsylvania. This book, her family has interesting stories to tell, but they also get preachy after each story, telling you what they think you should take away from each anecdote they share.
Maybe I'm just jaded by hating history class in high school, only to become really interested in history and politics in my 30s, but that's how I feel about this book. It seems like a great introductory book (perhaps a bit too homiletic), but I'm afraid of being let down by other books.