Monsters vs. Aliens starts quite like Independence Day - a rock from outer space alerts some station that is meant to find life forms in space. The story reminds a mix of a marsian invasion and the Fantastic 4. Whatever the movie is about - the 3D animation is absolutly fantastic.
The movie fits to all ages, as it is "light" (meaning, the story has no complications or complexity), has no sex appeal in it (it is quite rare to see a movie without any sexual context at all) and is funny.
I can't say it is the best movie I've ever seen, not even the best anumation film I've ever seen, but it deserves a quiet night at home watching DVD...
The story is filled with holes, and it seems as if the plot is being pushed forward and a lot of stuff is being ignored. It is also very noticable that the "main point" is the "message" of the film : accept those who are different from you, bla bla bla. Some characters had to be taken to the extreme (like a creature with no brains, a woman that is overgrown) to make this point hugh....
All in all, this movie is nice, and I would recommend people with children to rent the DVD for the children to see. If the message would pass through a 3D animation film - it worths the 3$ rental fee.