Well, I was just mimicing the sentiments of the OP. But as for 'competent' people, know of any major Perl shop that has moved from 5.8.x to 5.10? (With major I mean shops like Morgan Stanley, booking.com, MessageLabs, etc).
5.10 is kind of a special case, because p5p can't seem to release software.
I do consider anyone still doing new development with 5.6 incompetent. Likewise any version of Perl prior to 5.8.6.
I realize that's harsh, but unless you have a support contract with ActiveState or Sun or HP or another vendor dedicated to fixing bugs and ensuring that new software works with old versions of Perl, you're exposing yourself to all kinds of risk -- and you're doing the community which develops Perl absolutely no favors.