While I cannot comment on what other schools look for, I can tell you for us that GPA means much less than your ability to transmit character, emotion, and story creatively and effectively throughout your essay. Applications that tend to do well simply move us like a great film. They make us want to meet that person, have them in our class, help them succeed. These tend not to be the applications that aim to elicit sympathy and filmic passion (ie the ones that center on why you like film, why attending SC is important to you, what you're leaving behind, etc...) but rather the ones that present an element of life from a strong and unique perspective.
We also love people who are more than filmmakers. It's special for us when we see someone who has lived a unique or exceptional life and is seeking the opportunity to harness their experiences into the world of film. The funny thing is, most people have lived unique and exceptional lives, they just don't necessarily know how to frame it as such (and therein lies your greatest value as an applicant IMHO - how you frame your world).
There is no consistent decisive factor when candidates are perceived as equally deserving. The decision to choose one candidate over another can be anything from the makeup of the class as a whole (as we take pride in assembling a diverse group of students who can learn from each other), to small details in an application.
Here's the insider secret: what you want, is to not be in the part of the pile where we're comparing you. What you want is for your application to be so dominant that we MUST take you regardless of others. These applications are few and far apart, BUT my best advice to give you on how to be that person is this: for your personal statement write something that should be published. Write something that the reader will UNDENIABLY find meaning and entertainment in (regardless of whether or not they know you, care about you, or are interested in film). Write something that, if you were to read it in a magazine, you'd want to subscribe to that magazine! Much easier said than done, but we get them. And when we do, we will fight to have you in our class.