I agree -- I found it highly important. My stats were not great at all. I see all these stats of people who have yet to get accepted anywhere. But I had a damn good PS I think, and I believe that is what sold me to the schools I interviewed at. Think of the interview as a way to kinda back-up and support the voice they hear in the essay. I went to one interview, and the lady looked down at my essay and asked me why I didn't want to be a writer. It really is the one thing that can differentiate you from the rest, and where they can hear your voice and your personality as the other mentioned.
One problem with a lot of PS is that they're too bland and generic, and I hope you didn't make yours like that. It might seem silly to say, but make your personal statement personal. Reveal some of yourself to them, but don't let everything outta the closet (no jokes! 😛 )