None, really. I just like how its proponents can always win arguments by claiming to be more meta than their opponents. ("Sure, everything you made sense within your frame of reference, but there are no privileged frames of reference. Indeed, proving that there are privileged frames of reference requires a privileged frame of reference and is thus an impossible philosophical act. I can't prove anything I just said, which proves my point, depending on whether you think it did or not.")

(I don't take postmodernism seriously, but some of the ideas are philosophically elegant.)