Keanu Reeves

The Ultimate Matrix Collection DVD/Blu-ray has extras not on the 4K Blu-ray box set

Different colors compared to the DVD/2009 Blu-ray/Theatrical cut

There are some questioning around the color timings https://fanrestore.com/thread-3435.html

The Ultimate Matrix Collection DVD/Blu-ray has extras not on the 4K Blu-ray box set

Different colors in the 4K compared to the DVD (both original and 2003)/2009 Blu-ray/Theatrical cut.

There are some questioning around the color timings https://fanrestore.com/thread-3435.html

Shout! Factory 4K Blu-ray is more filtered than Warner Bros Blu-ray, although differences may not be audible.
(While the LaserDisc 2.0 is reportedly better clarity in dialogue?)

DV Plot. For those curious, the sculpture is still the altered one found on the re-issued DVDs, and previous Blu-ray.

5.1 audio on the Shout (either be 1080p or 2160p) was 16-bit, with more roll-off than the Warners one, the Warners was very similar to the NTSC and in terms of balance of the mix, while the Shout seems to be tinkered with, with the score at the beginning and at the end sounding worse on Shout.

Audio Comparisons: Slow.pics

For the regular commentary found on the NTSC DVD "Original Version" (there's no difference including the other NTSC DVD), Shout or Warners; the Shout commentary was just a bloated lossy transcode with some EQ. The best one was from either of the two DVDs.

Commentary Comparisons: Slow.pics

Now there's another commentary; it's basically the same commentary but has some parts different than the others, it can be found on EUR PAL DVD with subs for said commentary. The subs for it doesn't sync for the commentary #1 and vice-versa. Samples

UK Arrow 4K Blu-ray > US Shout! Factory

Arrow has a slightly better encode, edging out SF even with FEL, and has done some additional damage cleanup. Caps

UK StudioCanal has more extras

(Titans of Cult 4K Blu-ray has Dolby Vision)