They started the language re-design, circa 2000, and still haven't delivered, so the language became mostly irrelevant in the meantime (well, Perl advocates will fiercely claim that the new version, Perl 6, is actually usable while ago, and that old version, Perl 5.x, was actually updated regularly along the way, but I think at least the fact that the language is irrelevant these days is undeniable). The opinions about re-designed language were mixed: basically, Perl was already write-only language more or less, and this is even more true with the new version. There were some promising artifacts along the way, like Parrot, virtual machine able to support many scripting/dynamic languages (so that it would be possible to compile say both Perl and
Python, and then other alike languages, to the same virtual machine, and thus share the libraries, and work on runtime optimization), but this generated not that much interest from other dynamic language implementers, as more interesting and more actively maintained virtual machine implementations appeared in the meantime (like the work of LLVM guys).
Back on topic: the Downey book, used at this MIT course mentioned, is a very good introduction into
Python too. But the problem with
Python (both the language, and its standard library) is that, while indeed rather clear and simple language in the beginnings, it become more and more overloaded with features, so it gets almost equally hard to learn
Python as to learn
C++, and as it's much harder to write efficient code in
Python than in
C++ (even with NumPy and other goodies), I just see not much point in using it for anything except top-level, glue code...