Up is a perfectly decent movie - very good in parts - and Pixar maintain their tradition of well-developed characters and interesting storylines, whereas others in the digital animation world settle for far less (yes, this means you, Dreamworks).
The bad news is that it is in 3D. That means you have to pay more (higher ticket prices and normal discounts do not apply), and you have to wear stupid plastic glasses.
So why the 3D? Toy Story II was not a great movie because of the digital animation, it was great because it used that technique to tell a story with engaging characters. No need for silly gimmicks, thank you very much.
Unfortunately, the film industry seem to think that 3D is the answer to their prayers - here's something you can't get on pirate copies (or on the DVD) of the movie. If you want the 3D effect you need to go the cinema to get it. And pay more for the privilege.
Except I don't want 3D. If it were possible, I would have watched the normal (non-3D) version. No need to pay higher prices, no need to wear silly glasses. But I wasn't given that choice.
Of course, I'd be quite happy to watch the film on DVD in boring old 2D, and I bet it will cost less than two cinemas tickets. Which begs the question - is this really the answer to the film industry's problems? I'm saying no.