I saw him on the Today Show, and thought he was great! I usually don't like bio movies about singers where the songs have been rerecorded by the actor, because they usually don't have the energy of the real music, but this looks like it will be a big exception--

One of the more interesting recordings of Mack the Knife is a duet between Lotte Lenya and Louis Armstrong, recorded at the same time he recorded his hit version of the song--he was the one who added her name to the lyrics--