I quote what I posted elsewhere on this site since that sums up what I think of the 2004 version pretty well:
I didn't sour on the SE's until the '04 dvd's came out. Having a fairly keen ear for sound, and a good memory of the various nuances of the soundtracks, everything about the terrible ANH remix grated on me, and I don't just mean the obvious things like missing music. There's something "off" about the whole thing, which is hard to describe but definitely there. Much of the movie sounds as if it's been EQ'd towards the low end, giving it a muffled and distorted sound--you can especially hear this in the opening Star Destroyer flyby and the first stormtrooper shootout. Most of the Star Destroyer bass is supposed to be a 40 hz effect, but the '04 plays that down and emphasises a 60 hz tone in the mains to an unreasonable degree, while the strong higher frequencies that characterise the '97 mix in particular are practically unheard. Add that to missing laser blast sounds, background effects mixed far too loud, sometimes to the point of overpowering things that should be more prominently heard, wildly fluctuating quality of dialogue (announcements on the Death Star intercom actually being too clear, while people speaking onscreen are muffled), weird extra hissing and static added to the lightsaber duel, the music in general being too quiet--the result is an abomination, one that is practically unlistenable.
To add some more specifics to that: when Chewie 'escapes' his restraints and they start blasting at the guards in the detention block, there are three laser blasts before the officer in charge is shot, but the '04 mix is missing the blast sound for one of them. Some laser blasts in the Star Destroyer flyby and subsequent shot are also missing; others are out of synch to where they are supposed to be, and some new sounds are added which are distracting and unnecessary. Listen to the explosion when the stormtroopers break into the Tantive IV--it is extremely muffled compared to every other mix there has ever been. Listen to Obi-wan's lightsaber activation when he comes face to face with Vader--far too loud, and just 'wrong'. Multiple sounds of the TIE fighters pursuing the rebel fighters in the trench are synchronised incorrectly and otherwise distorted; likewise with Vader's shots that hit R2. The Krayt dragon call . . . yuck! Music reverb when the Millennium Falcon fights off the TIE fighters after escaping the Death Star is gone.
About the only good thing about the '04 is the LFE track, which has some very cool bass effects. Even that can be too loud at times (R2 falling over when shot by the Jawas), or even occasionally not loud enough (Star Destroyer flyby).
I haven't heard the 1997 mix in its native 5.1 format since it was in theatres, so I can't comment on it as a surround sound experience, but from I what I can hear on the vhs tape, it is infinitely better than the unfortunate dvd remix. I find it hard to believe that Ben Burtt was actually involved with the dvd in any way. Even if the '97 has less use of discrete surround channels and has the strange ".44 Magnum laser" sound, it is still better by far due to having a correct overall balance that isn't all that dissimilar from the original mixes. As such, I would be very glad for a copy of it. I'd like to combine it with an upmix of the '93 version and synch to the GOUT, but that's just a possibility I've been thinking of.