Sweeney Todd actually works better as a movie than on the stage, at least when Johnny Depp is on the screen. The music overcomes the staginess and melodrama of the story. Closeups make Sweeney Todd more tortured and less bombastic. On the other hand, I think that Angela Lansbury (who I’ve only seen in video) did a better job on the Mrs. Lovett role than Helena Bonham Carter.
It’s a pity Tim Burton couldn’t keep the chorus in the movie, though, as that is my favorite song.