Glad you liked it, mate! Still not terribly fond of it myself, but ..... SPOILERS in case anyone hasn't seen it...
The ending is superb. Pacino finally gets a shit-ton of karma dumped on his head. He is utterly destroyed. Diane Keaton looks at him with so much hatred in her eyes. Talia Shire is devastated by her part in the events. Everybody hurts, so much pain. And Pacino then goes on to live many years with that knowledge before he finally (mercifully) drops dead. And he didn't even want to be the head of the family in the first place! All set to Cavalleria Rusticana, one of the most beautiful pieces of classical music ever.
Shame the role of Mary wasn't played by a better actress, not the directors daughter, might have had even more impact if so! But the ending is, far and away, the best part of the film, IMHO....