IMO release cut is always the ideal option to appreciating an older work. not saying the creator cannot release variations on their work, but that the consumer is best served understanding the appeal of any work (movies, art, literature, music) in it's original "release". this is true for pretty much everything. if you want to hear the Beatles the optimum way, you should listen to a vinyl release, the media in mind when the albums were created. if you want to see Empire Strikes Back the best way to do it is via a VHS or Laserdisc release (the medium of the era).
the "final cut" is an important thing. often the creator wishes they had more time, as an artist you may even be kind of tortured by a self disgust with what you create, so you keep working on it, trying to make it better, going over and over every details, because it's "not good enough yet". when a final cut happens, it ends that process, the creative choices are locked in place. artists are always compelled by lack of time & other circumstances to go with a certain decision, they must be allowed to change opinions, to evolve the story & aesthetics, this is the creative process itself.
the final cut decision becomes part of the film's initial reception. it does not matter if the intent was to eventually change things and the artist is interrupted by a corporation. the result is the result. it is what it is. often when i make my own art, i could spend ages tinkering with it, never fully satisfied, and in order for it to be set free, it has to be finalized. finalization is a sort of death, it is the end of the creative process in a way. whether the finalizing it chosen by the creator or his investors/employers, it ends up coming out a certain way due to the real life circumstances that go into the film. these should not be ignored in favor of deconstruction or re-contextualization (a la postmodernism). these circumstances leading to the final cut are the real world intruding, giving painful birth, the imagined dream of this fantasy work becoming a real world product the rest of us can see and appreciate.
for these reasons, I think that while demos and special editions and directors cuts are great ways to get more out of a work or artist, the best #1 primary place to go will be original release. if for no other reason than to provide an accurate historical version of the work, perfectly preserved as initially released.