I’m not familiar enough with Andy Kaufman outside of Taxi to say whether or not Jim Carrey did a good job in Man on the Moon, but I did not think that he disappeared. I was still very conscious that it was Jim Carrey playing Kaufman. I thought that it was a peculiar choice to cast Danny DeVito as someone other than himself when most of the famous people featured in the movie plays themselves, but perhaps it was wish fulfillment-him wanting to be the person who believed in him & did his best to shield/nurture him. I think that Forman was aiming for the equivalent of a modern day Buddha tale by emphasizing Kaufman’s belief that everything is an illusion until he transcends himself and through his gags, life itself. I would have found him extremely annoying if I knew him in real life. It isn’t Amadeus, but nothing is.