I have them all (except KTMA) on DVD from either Rhino or Cheepins. And like JC wrote, buying the official releases means the chance we get to have more releases in the future.
Besides RVR II, if you don't, the thought of me playing daily with my Crow figurine while you stare at your empty spool of thread (just WISHING it were a Crow figurine) will haunt you for years. We cannot have THAT, can we?