It managed to capture the serenity, the adorableness and the utterly uncompromising brutality of the characters as they were originally portrayed in the book.
People should watch this movie. It teaches so many valuable lessons.
I saw NIMH first and read Watership first, so maybe that's why I prefer the NIMH movie and Watership book, but I don't remember the film being bad. There was also a CGI one made a few years ago that was pretty good, although the graphics aren't great-- feels a little low-budgety.