I haven't seen it yet, but opinions seem to be split between "Yay, Merida is doing thing because she's an independent young woman!" and "Merida is a selfish wangdoodle!"
She isn't selfish; she's a teenager.

I saw it with my girlfriend and one of her friends from work. We all enjoyed it. It wasn't the best Pixar movie ever released, but it was entertaining and fun to watch, which is the point of movies like this. It was also beautifully done. The music was pretty awesome.