Coming from a Perl 5 background, what are the advantages of moving to Perl 6 or Python?
In my opinion, Python's syntax is much cleaner, simpler, and consistent.  You can define nested data structures the same everywhere, whether you plan to pass them to a function (or return them from one) or use them directly.  I like Perl a lot, but as soon as I learned enough Python to "get" it, I never turned back.
In my experience, random snippets of Python tend to be more readable than random snippets of Perl.  The difference really comes down to the culture around each language, where Perl users often appreciate cleverness while Python users more often prefer clarity.  That's not to say you can't have clear Perl or devious Python, but those are much less common.
Both are fine languages and solve many of the same problems.  I personally lean toward Python, if for no other reason in that it seems to be gaining momentum while Perl seems to be losing users to Python and Ruby.
Note the abundance of weasel words in the above.  Honestly, it's really going to come down to personal preference.
I know Perl 5. What are the advantages of learning Perl 6, rather than moving to Python?