As of right now I don’t plan on tracking down the Definitive Collection or the THX (Faces) Editions because it seems redundant. I already own the 2-Disc DVD Editions of The Star Wars Trilogy from September of 2006 and the Letterboxed DVDs of the Original Versions included in those sets were sourced from the same Video Masters used for those specific LaserDisc Editions.
There is merit in having both the DC or Faces and the GOUT. The GOUT has much better video quality, but the LDs have much better audio quality.