Ugh, I really think that South Park is tremendously overrated. I mean, yeah, it's amusing, but when you compare it to something like the Simpsons or Family Guy, it's pathetic. Practically every comedic element in South Park is done better by at least one of the Animation Domination shows (except American Dad, but being better than American Dad is hardly an extraordinary achievement), and the few things that South Park does do better are pretty forgettable, in my opinion.
I admit that I haven't seen all that much of South Park, but I have seen enough to know that it just doesn't do it for me.