I would defintly go with Family Guy because I like the quick humour and gags and South Park IMO is trying too hard nowadays but I could see why the kids like it.
As far as this whole cartoon war goes, I dont understand why these legendary shows like the Simpsons and South Park feel insecure about FG. But its all good, they build the hype around it but FG kills them in like 3 seconds flat.
After all the hoopla of the Simpsons finally growing a pair and dissing family guy (which was funny, lets keep it real with the whole Peter Griffin thing)And Family Guy did comeback at the Simpsons. They did the Stewie running over Homer and Peter saying "Who the bad place is that?"
Family Guy has taken a shot at South Park before.
Peter goes into a rant about Fox, then Lois tells him "Watch what you say" and then Peter responds ""Why? What are they gonna do? Cut our budget so that we're crudely animated?" then he turns into a South Park looking version of Peter...
Pwnage
But for real y'all these "toon wars" are good stuff cause the writers step up a little. I mean the Simpsons is legendary but last few years its been like Larry Holmes in the ring looking Flabby and sick (which is understandable I mean after 17 years how long can you keep something fresh and it still is probably funny) but still even they got at South Park and Family Guy good. South Park even backed down and payed them respect.......South Park! Matt and Trey are vicious and dont care about offending no one and even they got humbled
So with Family Guy and South Park 2 shows that are naturally funny its gonna be comedy if they try to go back and forth and outdo each other. It will only suck if it reaches a point of overkill and saturation and other cartoons start little smacks with each other