I definitely agree that it depends on the show and the role.
However, I think I am better able to sit through a show with poor acting than a show with dreadful singing.
As a music director, we often cast based on singing over acting. I have found it's much easier to teach someone to act (at least so they're not painfully bad) in a few weeks than to teach someone with no talent/ability to sing within a few weeks time. But, again, it does depend on the show and the role.
"You just can't win. Ever. Look at the bright side, at least you are not stuck in First Wives Club: The Musical. That would really suck. "
--Sueleen Gay