I stuck 5.8.0 on a dev box a couple of days ago. It installed without a hitch.

I then installed the CPAN modules I use regularly or find vaguely interesting (88 at the last count, not including the ones that they depend on). They all installed with no problems (I love CPANPLUS)

I then did a global smoke test on all of the code that I've written. All tests passed (well, all them that worked under 5.6.1 did anyway).

I've been using perl since v4 and this is the first time an upgrade has been this pain free. It's certainly the first upgrade that's not broken at least one bit of my code. A huge vote of thanks to chromatic, Schwern, et al for all of those extra tests. It was worth it!

That said - if it ain't broke don't fix it is always my motto on production servers :-)