Moose has been used in production now for about a year in various companies (I know of 4 including my own work). I know of no major issues anyone has had.

It's speed has been improving in current releases, and the upcoming 0.18 release will provide the ability to make a class immutable, which will speed up class construction signifigantly.

As for correctness, this has always been my first concern, and I am very confident in it. Moose evolved from my work on the Perl 6 metamodel in which I spent about a year researching and writing several prototypes. I am also confident that all major bugs have been worked out at this point, and we have a very thorough test suite between Moose and Class::MOP with which to catch any regressions with. Also there are other major systems being built atop Moose (see Reaction by the folks at shadowcat systems) and what bugs they have uncovered have been fixed.