The Film is Better Than the Book. The TV Series is Better than the Film
That's what an article I read was saying. Same article was also claiming same happened for another very good Italian TV Series, "Romanzo Criminale".
I must admit I haven't read Gomorra book yet but, yes, I think the TV series is even better than the movie.
The characters are very well developed and, to my surprise, the acting is also very good (Conte, my favorite character), in fact in my opinion it is difficult to see good Italian acting.
Although I am from Naples myself, I was unaware and thus fascinated to see explained in details all the strategies Camorra uses to make their dirty business.
As a Neapolitan (citizen of Napoli), I hope this TV series receives the fame it deserves because despite what some ignorant people say, shading some lights on the dark side of Napoli, it is not denigrating the city, but rather raising awareness. Contrary, not talking about and showing all this is counterproductive for Napoli.
"Silence is Mafia". The stories depicted in this series should concern not only Neapolitans and Italians but the entire world because as you can read from Roberto Saviano's books (Gomorra, ZeroZeroZero), Italian mafia (Camorra, Mafia, 'Ndrangheta) are not a local phenomena any more. They have expanded to Northern Europe, South America, and North America (see recent arrests in NYC). Italian mafia drives worldwide economies.