Aside from the fixes, it's pretty minor. My goal was just to have some lossless audio sources for these movies, since I could already find lossless versions for the Star Wars stereo/mono audio.
The '80/'83 tracks from Harmy and DJ seem a little softer overall, ROTJ a little more than ESB. I think it's more than could be accounted for from just the lossy compression though, so I think whatever track Harmy and DJ used may have had some noise reduction and/or dynamic range compression applied to it, and mine must not have as much processing--or I'm imagining things. i.e. if I make a lossy compressed version of my files, it still sounds a hair better than the Harmy/DJ tracks (again, ROTJ a little more than ESB). That said, I still prefer hairy_hen's lossy 5.1 ESB track over my lossless 2.0 ESB track, so it's not the best thing out there.
The ROTJ fixups are pretty significant IMO. The major sync problem in ROTJ starts at about 47:37 (just after Luke's last scene on Dagobah) and continues until 1:38:33 (after some Ewoks jump over a log), after which it becomes a minor sync problem for the rest of the film (technically it exists but you don't notice anymore). Maybe it wasn't until I started doing subtitling, but now I can't stop noticing how badly off the lip sync is during that bad period, and ALL NTSC-based audio has the same problem. My version is the first version I've heard where I don't wince on and off for 45 minutes whenever Han talks (for some reason, it's always worse with Han). That said, if you don't make a practice of watching people's lips when watching the movie, you may not notice this at all. There's also just little audio glitches, such as at 3:23.903 when the audio just decides to go missing for 4 milliseconds. Again, it's not huge, but you can notice if you're listening carefully.
Anyway, don't mean to down-talk my own work. Obviously I think they're worth it for someone or I wouldn't have made them. But they may not be a huge improvement for most people.
EDIT: I will also re-adjust all of my subtitles to match this audio. For unadjusted NTSC audio, it'll just mean subs will be a hair late (compared to the audio--if you watch lips they'll show up at exactly the right time), which is actually perfectly fine. I just don't want them showing up EARLY, which is awful.