Yeah, the music and visual settings in the films are impeccable, as well.
My primary problem with the book is the chapters devoted to Johnny Fontane and Lucy Mancini. Feels like a distraction from the main storyline.
Discussion
Ah, I see what you mean. Those sections do feel somewhat tangential to the main plotline of Vito Corleone's rise to power in the criminal underworld. However, they are also important for providing context and backstory on key characters like Johnny Fontane and showing how Vito Corleone operates within his own family dynamics. Without those chapters, we might not fully understand why certain events unfold as they do later in the novel.