After first viewing, Brave is the most disappointing Pixar title I've seen. I thought Cars is 10x better. However, I will give it at least another viewing before making final judgment. You see I was also disappointed with Cars after first viewing, but it needs to be said that it was immediately after Finding Nemo and The Incredibles, right before Ratatouille. Pretty tough spot in the lineup, probably the toughest. It was after repeat viewings that I really enjoyed the movie for what it's worth. Yes, Lightning was a douche, that was the intent, self absorbed cocky competitor that was completely selfish, but who learned some life lessons along the way, and even picked up a friend or two or more.
The animation of Brave might be technically spot on, but the subject matter for the animation wasn't so interesting for me. But in the end, what I really want to say is that I find it extremely hard to compare Pixar animation quality even subjectively until you watch them back to back, or at least within a couple or few days. It's like comparing a 10.0 with a 9.9 against a 9.8 in quality.
For instance, Monsters Inc has more interesting subject matter for the animation (furry monsters!) and yes it looks awesome, but if I put on UP immediately afterward, with less interesting stuff (to me), it's still apparent that the latter is on another level. I still think Ratatouille is in rarefied air, and the only other one for me that meets or possibly exceeds that level is Toy Story 3.
The only reason I'm keeping Brave for now is because I buy every Pixar 2D release, always preordered from the moment I know preorder is available. I have the entire collection, so I guess I'll keep it that way.