I have never seen the show, but I often listen to the various recordings. The most compelling renditions, IMO--
Bea Arthur's coiled, snarling "Barbara Song" in the original;
Ellen Greene's "Solomon's Song"--she's altogether miraculous, playing the character as a tortured would-be Judas, delivering the well-translated lyrics with edge and poignancy through what sounds like bashed-in teeth;
Charlotte Rae's (yes, Charlotte Rae's) rendition of "Pirate Jenny" on a recording of one of those all-star benefits for something (perhaps one of the posters knows it). After this, she OWNS that song. Lotte who?
And, yes, Julia Migenes managed to bring a bit of operatic grandeur to her songs in the wildly misconceived movie "Mack the Knife" (other than her, it comes across as a bad summer-stock production of "Oliver!")
I ask in all honesty/What would life be?/Without a song and a dance, what are we?/So I say "Thank you for the music/For giving it to me."