Tread Perl5 as the stable branch of the language, and Perl6 as the experimental/growing version.

I cannot agree with per5 / perl6 in the above statement, however, perl5.8 / perl5.10¹ I could agree with. Perl 6 is still being defined.

1 - I hope I got the current numbers correct. I am currently stuck (due to vendor libraries) at 5.6.