It depends on your priorities. For Star Wars, the most “authentic” tracks are the 77 theatrical ones. 77 mono is probably what most people heard in theatres, but it’s the worst audio quality (recording of OTA broadcast, and academy mono wasn’t so hot to begin with). Stereo and 70mm are very slightly different content-wise (but not so most people would notice), and both sound great (lossless from Laserdisc, 70mm also uses some Blu-ray elements). For a stereo system, it’s safest to recommend a stereo track, as downmixing six channels can muddy things up a bit.
Then comes the 85 mix. A lot of people like this because it’s the home video mix most were used to in the VHS glory days – and because it’s a sort of mashup of the mono and surround mixes, it’s made up of all-authentic mixes, kind of a best of both worlds. It has great channel separation and no dynamics to speak of, but the audio quality is also great (lossless from Laserdisc).
The 93 mix is far from a crowd pleaser. While the audio quality is top-notch, authenticity goes out the window, as non-theatrical (and thoroughly unnecessary) elements have been added to the mix. It’s what (some) Star Wars fans hated before there were Special Editions. It’s also lossless from Laserdisc. I think it’s inevitable that any official OOT release would have this g****mn mix as the only audio option, which is why I made the comment you referred to earlier.
For Empire, the 1980 stereo mix and six-channel mixes on Despecialized are content-identical. There was a 70mm six-channel mix, but this isn’t it, and there aren’t any good recordings of it, and it went with a different video cut anyway. They both sound great (80 stereo and six-channel), lossless from Laserdisc, yadda yadda. The 1993 mix also sounds very good but is flawed, as it’s missing a sound effect during the snowspeeder crash. The 16mm mono mix is a recent discovery, sounds like crud, but is really interesting, and authentic.
For Jedi, all mixes are content-identical, and all sound very good. I think the 93 stereo might sound a little better than 80 stereo, but they are both lossless from Laserdisc, you know the drill.
Hopefully my repeated mentions of Laserdisc let joefavs know where the lossless sources come from–high-quality lossless audio for home video actually predates DVDs by quite a bit. Star Wars Laserdiscs released before 1985 have the 77 mix, between 1985 and 1993 have the 85 mix, and after 1993 have the 93 mix. Some Laserdisc audio was analogue, but we actually have digital captures of all of these (not sure which ones Despecialized uses, except 77 stereo is definitely a digital capture, because it was so hard to find digital audio on a pre-85 Laserdisc that we made a big deal about it when we found one).
For me? I always listen to the 6-channel mixes, and the downmixing doesn’t really make that much difference on stereo setups IMO, so I’d still listen to them there.