I'm mostly interested in auteur directors. And those work best for me when they write their own script. That means, I prefer those films by them, where they took part in writing the screenplay.
To explain with well known favourite directors of mine:
So I prefer Kubrick's ideas about 2001 to those of Arthur C. CLarke.
So for instance concerning Aronofsky's films I prefer Fountain to Black Swan and Pi to The Wrestler.