> "3. sed is more performant (or so I hear)."

There are regexes for which awk (maybe sed too?) will perform at a reasonable speed while perl is incredibly slow. Graph: http://pdos.csail.mit.edu/~rsc/regexp-img/grep1p.png Article: http://swtch.com/~rsc/regexp/regexp1.html

Perl...could...employ much faster algorithms when presented with regular expressions that don't have backreferences.