I don't enjoy either Harvey's or Rosie's voices, particularly, and I'm one of those people who believe that singing well in a musical is important, regardless of whether you can act or not.
(At $100 per ticket, I expect both.) My reaction to this is that it's probably a good thing it's closing in January.
"And the postman sighed as he scratched his head, you really rather thought she ought to be dead..."