Brando was just what this film needed. Not so much Nicholson, though...
I thought Brando's appearance in this film, which made the "regulator" a deliciously and unexpectedly offbeat character, was just the ticket for this movie. It would have been a much different, perhaps even boring, movie, without Brando. I like Brando in a few other films - "The Island of Dr. Moreau" and "Apocalypse Now" - for just that same reason.
As far as Nicholson's characterization of Tom Logan, I thought it was okay, but he seemed awfully stiff compared to Brando's smooth, almost effortless performance.
The one character i didn't really "get" was the daughter, played by Kathleen Lloyd. Her part was badly written, and poorly portrayed. Nice lady to look at, but sheesh, I coulda' done without her trying to instantly play sexually liberated woman throwing herself all over a scruffian like Tom Logan. totally unconvincingly played!