I just came home from seeing "Up" in 3D and despite my seat being a little damp from their cleaning last night Up ties Watchmen for my best movie of 2009 so far. It's impossible to call one better due to the major differences between them, however it's hands down one of the best CGI/3D films I seen in the past 4 years or so.
Pixar once again proves they are they very best at what they do. The movie did follow suit of Finding Nemo however, opening with a joyous scene and then wham, tragedy. I won't say what happens but it's very well done, hell the whole movie is well done.
Anyways if you really like going to the movies and want to laugh and maybe even cry a few times Up is the movie I recommend to see. If you like things to be in 3D see it in 3D, however if you want to say a few bucks the 2D version should be perfectly fine. Plus the 3D version is a bit darker in coloring due to the use of polarized 3D glasses and that's sort of a bad thing. Your not seeing the full color, It worked with Coraline since that movie was dark as was. However it sort of sucks not seeing it fully the way it was meant to be while in 3D.