Well, perhaps one can treat my comment as good part fondness/nostalgia.
Although, I clicked through the pop-up link, to find a fairly brief and limited set of points in a short, single critique of the 4th edition.
I don't know... It's been a while, but I still remember "Programming Perl" as providing not just the what but a good dose of "why" and context.
A lot of people who "don't like Perl" don't seem to understand that, where it's coming from, both philosophically and systematically (if that is a word and I can use it here).
"Programming Perl" is not, in my opinion, a beginner text. Randal took care of that contemporaneously with "Learning Perl". But it was, and -- current shortcomings aside -- perhaps still is, a good post-beginner text.
It also remains "timeless" for me, in that it was a good, engaging read. In my opinion, more texts should -- if clever enough to -- dialog with the reader rather than spewing at them.
Anyway, I don't mean to put myself in the position of defending Larry et al.'s tomb in this post-post-modern world. I'm hardly qualified to begin such a task.
But even if it's not currently the best reference, or even recommended as such, I think it may remain a decent example of how to write one.