I think of GREETINGS and HI, MOM! as falling-apart crazy-glued anarchist masterpieces and SISTERS as a transitional work that gives away a great deal about the secret congruence of De Palma's two phases. As Hitchcock becomes important, naturally form also becomes important. When form becomes important, De Palma becomes a new intelligence. A slightly different form of ruthlessness, but he's still basically naughty.