Perl's used more widely than Python, if you look at job trends -- but then again, you have to consider that Perl 5 was more popular earlier, so there's a lot of entrenched usage. Python may or may not have more new projects written in it; the statistics are difficult to interpret.
You can get by knowing one or the other well. Perl's advantages to me are the CPAN, the tooling culture, the testing culture, and a very pragmatic approach to getting things done without the language or ecosystem dictating how.
Python's advantages are slightly cleaner defaults in Python 3 and the fact that all code looks basically the same. (I'm not sure I see that as an advantage, but other people do.)
You can get by knowing one or the other well. Perl's advantages to me are the CPAN, the tooling culture, the testing culture, and a very pragmatic approach to getting things done without the language or ecosystem dictating how.
Python's advantages are slightly cleaner defaults in Python 3 and the fact that all code looks basically the same. (I'm not sure I see that as an advantage, but other people do.)