If you loved the book there isn't any reason why you shouldn't purchase this series. However, even if you haven't read Evan Wright's Generation Kill this is an excellent series that you should seriously look at.
The quality of this show is excellent like HBO's other well known war series, Band Of Brothers but the execution and final result cannot be any more different. Some viewers might be disgusted with the language, but it's small fry with what these men have to go through with.