Saw it some time ago and didn't like it. I don't recall everything but IMHO it was too romanticizing and the 'friend' from Corleone (the good guy) should have been killed and fed to the pigs in the first episode.
Also things were changed as far as I can remember (and know): 'La Matanza de Viale Lazio' for example. That pissed me off.
And Riina, especially with his bad make-up to make him look older, reminded me too much of a certain porn-actor whose name I can't recall at the moment.