Perl 6 tries to address many of the Perl 5's gotchas, including OO. Throw in familiarity into that and a lot of new features that scratch various itches and you would understand why some Perl 5 people would want to try Perl 6, but not Ruby.

Maintainability, productivity, etc. of Perl 5 is on the same level with Ruby. And I don't think Perl 6 improves on that, so it's probably the same too.

Personally I don't see any benefit for anyone to switch between mentioned languages. They all have similar problems.