It's definitely a must-watch, though I still believe it could have been made better. For one, none of the characters really grew from the experience and Mary shifted the blame on the flowers/berries instead of accepting and understanding that she was partly to blame as well. The witches school didn't seem very developed either, the students didn't really seem like characters, just pawns [I'm not sure if that is the correct wording].
I'm still a big fan of the movie, I just think it was a little rushed than it ought to have been.