Family guy of course heh: its stupid, raciest, stereotypical, violent, heart warming, demented, evil, and insane......everything that americans love to watch in one stupid ass show.
Simpson has been going haywire in the past few years. It has gone stale over time. I don't like Family Guy frankly but currently, it's much better.
But if we were to compare the original seasons of Simpson with Family Guy, I'd say The Simpsons. Those were genius and since I grew up with them, it got nostalgic factor.