I think Tom Waits is a better actor than a musician. I'm wrong, right?
He's basically playing himself in both contexts, but he's definitely a better musician. Though you have to have a taste for the music moreso than the acting.
I've heard about 20 of his songs over the years, and I treat them like I treat deep-fried alligator chunks...a nice little novelty that isn't all bad, but not something I want to make a regular part of my diet.
But his acting is pretty cool. I've seen him in co-starring roles in Wristcutters: A Love Story (really good movie), and The Imaginarium of Doctor Parnassus, where he played Satan, and I thought he pretty much stole the show in both films.
Well maybe not Wristcutters. The guy who was playing Eugene Hotz stole the show.