I've been aware for some time that the creators of South Park do not care for Family Guy. It seemed in keeping with the 'bad boy' image of South Park to publicly hate something that's popular. And since Seth Macfarlane was a new kid on the block, it made sense. But recently, I stumbled across this Youtube clip (just audio) about their reason for disliking. Have a listen:
Their view is actually quite nuanced and considered, as you'd hope from highly successful multi-millionaire comedy producers. And I respect them for going on record for giving their opinion robustly, and without saying 'It's just a personal thing but...'
In case you can't be bothered to listen to the clip, their view is that Family Guy has too many unrelated jokes in each show. This is true. The show keeps cutting away to flashback or fantasy scenes, often introduced with lines like "Hey, this is worst than that time that I..." etc.
I agree that it makes the overall show less elegant and well-crafted. To be unequivocally wonderful, a statue should be chiselled from one rock. Personally speaking, these unrelated flashbacks and set-piece scenes don't ruin the show for me, especially since the show is animated which means that these jokes can be done at lightening pace without harming the overall narrative - even if the overall narrative is not helped.
When I first saw Family Guy (I think I saw the second episode, where Meg knocks out cable) I thought it was one of the funniest things I'd ever seen. In fact, I made quite a lot of my friends watch it. I was pretty evangelistic about it. I still like lots of it, especially when they play with the pace of animation and suddenly slow things down massive (Peter trying to throw a frog out of the window and taking nearly a minute to do so it joyously hilarious).
In actual fact, I've gone off Family Guy in later series because I found it's moved away from 'edgy and funny' and towards 'vile and mean'. Quite often it's unnecessarily scatological, which is not really to my taste. (Which also explains why I've never liked the jerky, spikiness of South Park) And they seem to make personal jokes about people who don't deserve it which can be morally reprehensible.
But it's great to think about these things and argue about them, without descending to personal abuse on one side or just saying everything is a matter of taste on the other. Or even worse - saying nothing at all.