This is one of my favorite movies. If you are looking for a fast-paced "serious" science fiction movie, then this may not be for you.
It is an old-style fairy tale, a fable, set in the real world. It is nonsensical as many children stories are. In fact, this is actually a story he would tell his kids at bedtime. It has a scary edge. I mention this because that was the sole reason one of my friends didn't like it and just turned it off. The wolves scared her too much and she isn't into scary or fantasy movies.
However, if you like movies that take their time and use symbolism, deeper messages, etc... then you may love it. It is all this with an assortment of quirky characters and beautiful cinematography.
I think the reason why many don't like it is that some of the characters are so interesting or comical, you can totally imagine them in hilarious important scenes, and it's disappointing that they weren't used more. That is my sole complaint, and I wonder if it got shortened and edited too much as happened to The Last Airbender. But if that was not the case, the beautiful messages still come through.
I think another reason some don't like it is that some of the messages can't be fully appreciated unless you are a little older and/or have had some meaningful coincidences in your life that can only be explained as miracles. If you have, then this movie is a beautiful psalm to that type of thing many of us have experience.