I can be far more forgiving of blowing a lyric than of just plain being off key and low-energy sloppy. That was what I didn't like.
I'd also like to say that I felt the show relied too much on backing tracks. I'd much rather they skipped some of the ambience and dramatic introductions to songs in the live performance and get a dedicated keyboard player and electronics engineer on the stage to do more "live friendly" interpretations of the tracks.
Eh, it WAS and early performance and I highly suspect that the performances have continuously improved over time. Still love em and glad I have the disc.