The book was an interesting read for me, as I've never been in the military myself. It was somewhat true to a roommate of mine who was in the corps, who said "it combines the aspects of a fraternity and a gang."
The author's premise is that he basically hated being a marine, even though he was there by choice. Beyond that, everybody walked around with a very cynical "i'd rather not be here" frame of mind.
To finish it out, it's more a book about how he came to be a marine and his experiences while in the corps, rather then a strong dialog about the job of a sniper or a diary of his combat experience. In fact, according to the author, he makes it through all of Desert Shield/Storm without ever firing his M40.