Some arguements from both sides and my opinions

family guy dvd

family guy series dvd is funnier
You tend to hear the arguement that it's really all about more from the family guy dvd box set side, and I guess it's true, i think there might be a bit more laughs, but that all depends on how much you get, if you spent 5 years in a cave on Mars, the simpsons dvd box set would be far funnier, it all depends on how much attention you pay to pop culture and how funny you find it.

the simpsons dvds has been going too long
I think that this may be the weakest arguement there is, the reason the simpsons dvd has been going on so long is because so many people continue to find it funny, maybe if it wasn't for the departure of the genuis Seth MacFarlane and the best charater, Stewie (although as MacFarlane provides Stewies voice they might have actually have been one event) family guy dvds could have lasted longer, but without MacFarlane, I can't see it happening, and even if he returns, the show might "Do a Dallas" and struggle with a character's return.

simpsons dvd set has more to it than funny
That's definately true, but you don't watch the simpsons dvds or Family Guy to see lessons learnt or romance or anything like that, you watch it for laughs, so that looks like another fact that means squat.