Sources using this master (that I know of) as of the time I'm writing this: Stan. (stan.com.au), Disney+ (disneyplus.com).

Quick TLDR: Consider these copies as if you were traveling back in time and watching these when they originally aired, except in better condition, 1080p HDTV H.264 Progressive format. They are better than the DVDs in terms of condition but have various TV censors, bleeps, and cut/shortened scenes, so it's up to you if it's an overall better copy.



Source information:
Broadcast copies; They all have the TV broadcast differences to the DVDs listed on movie-censorship.com, including audio bleeps, video cut or shortened scenes, e.t.c.
Broadcast region unknown, but possibly intended for German airing; Evidence for this is in S01E05 where a german-exclusive deleted scene was kept in, S09E01 is a two-parter which matches how it aired in Germany, coincidence?
Copies match FOX Studios Animation Archive Portal; This is a portal staff can use to download fox animation content for making social media posts, QA, to use for making DVDs, licensing, e.t.c. The copies on here are essentially the digital master copies, there have been rumors that FOX destroys originals after digitally archiving and if that's the case that's bad, see CONs below. This also means all the issues you see like the infamous flickering and pixelated freeze frames and edits, are not an issue with this copy, there IS NO FIXED COPY. The episodes are like that forever until it gets re-animated or the original project files are found (unlikely to happen and by FOX archiving these, proves it). How do I know these copies are from this portal? Because I was provided S01E01's video track from this portal about a year ago and can confirm they are the same.
This is NOT a typical upscale; The copies are HD. However, it is an upconvert, meaning the animation was carefully resized to fit a 1440x1080 (4:3 1080p) frame. However, this is still not a typical upscale where someone grabs a DVD or such and upscales to a new resolution. This is evident simply due to the PROs listed below as well as the fact that scenes that include live-action video, e.g. S02E03 Da Boom's ending proves this. You could think of this as a file exported as 1080p, but not directly animated in 1080p, like almost all anime, e.g. Re:Zero being animated in 916p or something.
SD-Era Overall Quality; Season 1 is by far the worst condition (regardless what source), Season 2 is better, and Season 3 onwards is very nice with only the occasional problem (again regardless what source). Funny enough, Season 7 is one of the worst in terms of sharpness, feels blurry with the colors possibly a bit off too, but it's still nice.




PROs:
DVD-caused issues are either gone entirely, reduced, or not as bad; DVD-caused issues can include burn-in interlacing, chroma, haloing (aka glow), flickering, noticeable compression on high-motion, weird vertical pixelated lines (I don't know a word for it).
Detail retention is a lot higher; On the lines, backgrounds, or in some scenes with a high speckle count background/floor, the difference in quality and condition can be quite noticeable.
Sharpness of lines are great; This is mostly due to the haloing of the DVD being reduced or mostly removed, however, it has a different form of haloing known more as double-ringing which in my opinion is less of an eyesore and less obtrusive of the art style (but not ideal either way).
Chroma location is fixed; While the DVDs chroma location cannot technically be incorrect, it technically is. The DVDs use Chroma-location of 2 (top-left) or 1 (center) depending on the season. The problem here is that is not what the ITU e.t.c recommends for MPEG-2. Players like VLC, MPV, MPC e.t.c use a static chroma location to playback based on the codec instead of reading it from the metadata (I find it stupid, and that is more of an issue with the software, not the DVD, but alas). These copies use the ITU recommended H.264 chroma-location so players like MPV e.t.c play it back correctly.
Chroma is a lot higher condition; These copies have much better chroma quality/accuracy/sharpness/whatever you like to call it. This means issues like chroma droop or edge-softness caused by bad/soft chroma do not exist in these copies.




CONs:
24000/1001 FPS, the show was animated in 24 FPS and post-production editing was done in 30 FPS (possibly NTSC 30 specifically, meaning 30/1.001fps, 60i); Post-production being stuff like credits on screen, fades in/out, Computer-done Zooms, Pans, Edits, and Freeze Frames. This means we are potentially missing out on a bit more fluidity.
AAC audio; Compressed, but I genuinely can't tell any difference even on my nice $300 headsets.
2.0 channels audio; The DVDs have 5.1 (6 channels, one being LFE) for Season 4 onwards. Could be potentially missing out on entire audio effects.
TV broadcast copies; Bleeps and differences to the DVD's including cut scenes or shortened scenes (or in some small cases scenes being animated differently, as in animated less of a budget compared to the DVD, usually to do with the backgrounds having less detail)




ERRORs (found so far):
S01E05's chroma location is incorrect, it was encoded in a way that the input chroma-location was loaded in most likely 0 (center-left) and then encoded in a more right-sided chroma location and when played back on most software results in the video color looking as if its been shifted 2 pixels to the left, very distracting and makes it look worse quality than it actually is.
S01E05 left in the german-exclusive deleted scene to do with President PEZ Dispensers. This was removed from all US broadcasts as well as all the DVDs except the German DVD.