The Secret of NIMH is an animated movie of the same vein as Watership Down. It presents real life situations of hardship, perserverance, and family in a fantasy format.
I would easily recomend this film for all ages. HOWEVER i would strongly recomend a parent watch it with any young children for the first time. There are some fairly scary moments in the movie.
As the twists come thick and fast and the plot gets progressively more and more baroque, Branagh shows himself to be at least as intelligent as Brian De Palma in delivering over-the-top stylistic filigree.