There are bugs in 5.8.0. There are bugs in 5.6.1. There
have been bugs in any version of Perl that was released.
There are even bugs that take many years to be found, or
years to be fixed after they have been found.
What's important is, "will the bugs effect your system"?
You can only find out by testing (you do have a test system,
right? ;-)). But I would also like to point out is that
running the latest release isn't a goal in itself. If you
run problem free with 5.005_03, and you don't need any
features from 5.8.0 (or 5.6), why upgrade? It's not that
new versions of Perl are faster (they might be faster in some
areas, they are slower in others, and while it will differ
from environment to environment, newer versions of Perl tend
to get slower overall).