It's the only high-level language I know of that only has reference counting for memory management.
It's also the only high-level language I know of that can't really be parsed ("only Perl can parse Perl" they say).
It's a dead language really, you can also see this from the number of noisy evangelists vs. professional users nowdays (and that comes from someone who has used Perl almost exclusively for the past 10 years), if you couldn't see it from the diminishing quality of important modules on CPAN (e.g. I pulled my hair today over JSON::XS generating '-inf' from values on one side and crashing on the other side while trying to parse it).
So, I'm learning Go now and improving my JS skills.
Actually, where I work, we use Perl almost exclusively. I don't know a single person who I would consider a "noisy evangelist" - we just quietly get stuff done.
There is a Steve Yeggie quote, though its not necessarily praise for Perl, which always pops to mind when people have a rant about Perl:
'As I've done for a great many other programming languages, I've bashed on Perl's technical weaknesses at length in the past. To my continued amazement, the Perl folks are the only ones who never get upset. They just say "Haha, yeah, boy, you're right, it sure is ugly. Heh. Yeah, so, um, anyway, I'm going to get back to work now..." It's awesome. I've gained so much respect for them. It's almost enough to make me go back to programming in Perl. Well almost.'
Edit: Quote reference: http://steve-yegge.blogspot.com/2006/10/egomania-itself.html
I was bit quite nastily by the lack of garbage collection in Perl just a couple of months into using it.
However, perl proved itself as an invaluable tool for quickly trying out ideas, and I was loyal to it for at least 10 years. Perl just wasn't able to grow as strong as the alternatives did.