It's good, but the list of "success stories" that he links is not very impressive (scheduling software for NASA is by far the coolest stuff). Python has http://www.python.org/about/success/; Ruby has e.g. (early) Twitter and Metasploit; PHP has e.g. Facebook and a crushing market share; C has a zillion stories starting with the free Unixes. Yes, these languages have their issues. No, scheduling software does not beat Unix.

I'm glad Weinreb brought up extensibility. Almost every good idea from Lisp has been recognized and widely adopted over the last fifty years, but its remaining claim to uniqueness and power is letting you make effortless changes to syntax and evaluation. You haven't constructively critiqued Lisp if you don't address that head on.

As for "whatever you're reading this with [...] was written in a variant of C", well, yeah, that's why it's crap that blows up randomly. This is a problem that the industry is very slowly nerving itself to solve.

It's also almost longer =)