Perl is an okay language, but is spoilt by the culture of developing in it, which is often about writing compact code, using various shortcuts or symbols, and it has loads of wacky syntax that is a nightmare to read, so people often don't write easy to understand code.
That very much depends on the coder in question, and the purpose of said code.
(I'll write code differently for production environments than I will to solve a quick puzzle for myself).
It should be noted that a sufficiently good/bad (take your pick) coder can write obscure code in any language. Perl isn't really any better or worse for it, but it has a poorer reputation.
Perl programmers go for speed and therefore it is often very difficult to read their code if you are a beginner.
Do you really think that Perl coders are so fast with devising code that cutting down the amount of typing they do speeds up the process?
If you're talking code execution speed, then well, you learn when to optimise and when not to.
Perl's a very legible language when written right; one of the problems with this is that as a consequence, it can be fairly illegible when it's not.
The thing people haven't mentioned is CPAN, which is really the core strength of Perl – vast amounts of code written by others, so that you don't have to.