This is my opinion, but I think people enjoy Pixar movies better. I'm not sure how Cars will do, but in the end, Pixar movies triumph.
Well, not everyone is the same. People have different tastes and there are people whow prefer DW. Also you have to remember that Pixar films are marketed MUCH, MUCH better than the not-very-good marketing at DW. Pixar has Disney behind them for crying out loud! Of course there films perform better on average, but that doesn't mean they ARE better. More people go to see Pixar films because, like Ben said, more people are aware of them. Look at Sinbad and Finding Nemo....everyone in the free world saw Nemo that summer but I could count on one hand the number of people I knew who had even HEARD...no, not SEEN, HEARD of Sinbad.
DW didn't have a chance, and Sinbad was a complicated film with a subtext that was much harder to sell than "Overprotective father loses his son" in a big colorful ocean. Pixar has a much easier job marketing their films not just because of the Disney connection but because their concepts can be summed up in less than a sentence. That doesn't make their films bad but it does make them much more likely to succeed. (and less likely to be seen as deep and profound as the years go by. In my opinon. Because it's hard to see college media professors writing essays on Woody and Flick the way they do about Pinnochio and Bambi.)
It's like Bush winning the election the first time....he won the big states so he got to be prez, but he didn't get the popular vote. I sort of see the animation situation as the same thing. Pixar has the goods, so they get the "big states." DW well....they have Rhode Island, Vermont and Maine. Those states don't win an election. It's not their fault they couldn't sell a film about a pirate with a guilt complex.

Maybe if they had also had a powerful father/family who backed them (even with a C average, and yes, the lack of a powerful antagonist in every single film), they might get to be president too.
(BTW I'm just using this as context, I don't hate Bush or anything.

I voted for him both times.)
You can’t just have your characters announce how they feel! That makes me feel angry!