I muxed a version of the full film (ANH) with 3 audio tracks: 1) DC48 encoded with Aften, 2) satanika's 5.1 upmix of hairy_hen's LFE mix and 3) the retail GOUT mix, so I could switch back and forth on the fly and make a better comparison.
The DC48 was as expected and as previously posted, it was a nice full and rich sound, within the limits of Prologic. It definitely lacks a discreet channel sound of your 5.1 or any modern film, but it feels nicely integrated within it's range and limitations. I've since watched the whole film with it and it works for me as the definitive 1993 mix.
I only listened to a few sections of the retail GOUT mix for comparison to both other tracks, and really there is no comparison. It just sounds very thin next either of the other mixes.
I haven't watched the whole film with the hairy_hen/satanika 5.1 yet, but I spent some time listening to many more sections throughout the film including the Battle of Yavin. First off, I didn't detect any significant degradation or other negative artifacts of the upmix process (at least to my untrained ear on my budget 5.1 system). I had wondered if that might be an issue, but I didn't hear anything that would detract from my viewing or listening experience.
In general, the hairy_hen/satanika 5.1 is crisper, with sharper separation of sound and a nice booming low end, especially on the space battle scenes. For the space scenes most of all, this 5.1 really makes the sound more powerful and gives the audio more of a pop, in the positive sense of "visual pop", the audio equivalent of richer colors and contrast. Among other qualities, the dialog also benefits from a clearer, more discreet sound.
Now, being able to A-B listen (switching back and forth from DC48 to h_h/s 5.1) I could hear another quality that was different between the two, besides just the LFE and 5.1 upmix. In comparison to DC48, the h_h/s 5.1 mid and high ranges seem to be boosted almost like turning up the treble, so the sounds are sharper. It's especially noticeable on dialog and horn instruments in the music.
I haven't heard hairy_hen's original 2.1 and I didn't have it on the video for comparison, so I don't know if that quality was part of hairy_hen's original processing or if the effect is only present on the 5.1 upmix. I didn't recall seeing a mention of additional sharpening or processing of the the mid and high ranges, so I can only guess that it might be due to the ATSurround process. I'm not sure if part of the low end was stripped from the main channels and redirected to the LFE along with the actual LFE track or if the ATSurround matrix algorithm just has the quality of dialing up the "treble" as part of the process.
I wonder if anyone else noticed this quality of the h_h/s 5.1 mix. It may just be me and it may only be detectable when switching back and forth in a direct comparison to the DC48 track. It's not necessarily a negative, it's just different when compared to the DC48. Obviously, this effect also contributes to the crisp, sharp and more discreet quality of dialog, fx and high end of music (horns, etc.).
Scanning through the film to test various sections, I noticed a only few areas where either the overall effect of the LFE or increased crispness/treble didn't quite feel right (to my back-seat, amateur mixer's ears).
04:42 - 49 The ambient ship sound of doom as Vader walks down the hall seems a bit much here with the boosted LFE, especially in comparison to the intent of the sound in the DC48. There is a similar, but more subtle effect throughout the film in this sequence and with the Death Star interior ambient sound, but this short section is the only place where the LFE seems overdone in relation to the rest of the sound and surrounding shots. I know it's intentional, but the relative weighting of the low end in the DC48 mix works better for me.
44:14 ... Throughout sections of the Catina scene between music and dialog, the room tone/background ambient noise and voices/tape hiss(?) is a bit more prominent and over-emphasized by the crisp/treble quality of the 5.1 mix, in comparison to the DC48.
1:31:32 ... The Falcon interior ambient noise (jet plane interior sound, etc.) takes on more of a hissing/noise quality under the music due to the same crisp/treble values.
I didn't listen and compare the entire film, so there may be other sections with similar issues. I have the feeling that these areas only stood out to me because I was switching back and forth between the DC48 and h_h/s 5.1 and intently listening for differences. I doubt they would be very noticeable during a normal viewing of the film with the 5.1 track alone.
In conclusion, the h_h/s 5.1 passes with flying colors as a great alternative track. It's very listenable and watchable and really dials up the intensity of the space flybys and battle scene a few notches. The dialog also has a more discreet quality more like a modern 5.1 mix and it's easier to pick out than on the DC48. I just watched the full film with the DC48 Prologic and I had to turn my receiver up a couple notches louder than I usually listen to 5.1 to get the right feel of sound I'm used to.
My comments are only intended as constructive feedback and to compare notes with what others are hearing. I'm especially interested to know if anyone else is hearing the crispness/sharpness of the 5.1. I wonder if it's only on the 5.1 or also on the 2.1 and if it's due to ATSurround or some other filter or perhaps it's an unintended effect of part of the editing or upmix conversion process.