Having both read the book and watched the series, the series diverges from the book in many instances. The book itself is embellished by the author, your choice as to how much.
Better book is "One Bullet Away" by Nate Fick (Bravo Company, 2nd Platoon commander depicted in "Generation Kill"). Probably much more accurate account, especially of his problems with the Company commander ("Encino Man") and "Kasey Kasem". It wasn't nearly as dramatic as it was protrayed in the series, which was even more dramatic than the book. I think Fick has been critical of "Generation Kill", calling parts of it BS.
Two of the Marines in the interview with Evan Wright were "technical advisors" to the show, Reyes and Kucher. Reyes comes off as a complete douchebag. Not sure about Kucher.
Anyway, my 2 cents.