While I like the original 1978 soundtrack, the songs in it are a little dated at this point. This recording not only is an update of the original show, but is the complete play, spoken and song, which I think works better. I think you get more from the music, when you hear the dialogue that was written to be spoken with it as well, and the performances are very good.
I bought both this and the original at the same time. I think I will probably be listening to this version while the other will end up in the CD collection.