I never read the Orwell book... but i do have two children under 13 years old and we enjoyed the movie. it is a kids movie, so remember that when you sit down to watch it, but it did a good job of stressing the class warfare.
Again, its a kids movie so please don't expect Citizen Kane. but if you want a well voice acted 90 minute entertaining flick that is DESIGNED FOR CHILDREN, you're in good hands.
Also, in case you were unaware, this is a kids movie, not a proper recreation of a literary classic. hope that helps.
TL;DR Its a kids Movie. a good one at that