I thought the book was great fun- maybe not a masterpiece but enjoyable - I’ve re-read it several times. The Lucy story is somewhat cringeworthy but I didn’t mind it that much.
I listened to The Godfather as an audiobook recently; it was my first time “reading” the book. Puzo is great at world-building and describing the shifting alliances and betrayals among the Mafiosi, but his dialogue and characterization is sometimes surprisingly clumsy. Still worth a read, I’d say.