I saw this with my mom on Sunday and we both really enjoyed it.
I think this probably has some of the best music of any Disney movie. I'd personally put it right up there with Beauty and the Beast, Little Mermaid, Aladdin and The Lion King.
As for the movie itself, I thought it was great. I thought both sisters were great characters, thanks in part to outstanding performances from both Idina Menzel and Kristen Bell. The animation itself is beautiful. They did a great job with the snow which I know can be a big challenge with CGI animation. I also notice that Anna actually has freckles, which I don't think I've ever seen on an CGI animated character before.
The story was great too, with some surprising twists. Honestly, if Disney just let the people responsible for this and Wreck-It Ralph handle all of their animation for the foreseeable future, I think I'd be very happy indeed.
I really enjoyed the humor in this one, it had quite a few very funny moments throughout the story.