in reply to
Arguements for upgrading from Perl 5.8
Which versions of perl are available in your OS vendor's repositories is all about running the scripts that you are paying support for.
Instead of a version that is in the repositories, you probably want a home built copy of perl in some place like /usr/local/bin . This way your scripts can call it for the latest in Unicode/RegEx/Feature support and the vendor's perl scripts can run off the vendor's version.
Building Perl on Unix/Linux is easy, and since you won't be using the system's perl for custom coding, you won't need to update CPAN modules against the 5.8 lib/ directories. In fact keeping your modules up to date against a current version of perl will probably be (only slightly) less effort.