Dayton Lummis

The older track sounds significantly more natural. The WAC BD uses a new mastering which sounds much worse. A lot of the dialogue sounds off, sort of echoey, garbled or even artifacted. Its overzealous click removal also erased some sounds. Its only positive is a new EQ that brings out the bass more making some of the score more effective.

It seems that the new mastering likely uses AI "enhancement" or some other form of aggressive filtering, resulting in extended peaks despite losing real high end detail (most pronounced on sample 3).

Samples (WAC is mislabeled as UHD)

Commentary is mono on the Blu-rays and panned stereo on NTSC DVD (different channels for each speaker).

Shout's BD has both cuts of the film in addition to the 3.0 stereo and  2.0 mono mixes making it the first time the full theatrical cut is available with the 3.0 mix. The new commentary is good. The 3.0 stereo sounds wonderful and the mono sounds solid.
That's where the positives end. This is the same terrible Universal DVD master slapped on a Blu-ray disc with a terrible encode making both versions share the disc separately taking up more space. This master was already poor for DVD and is nearly unwatchable here on the Shout disc. It looks virtually identical to the upscaled DVD most of the time with only a bit less noise due to it being 1080p. This is one of the most appalling cases of "DVD master slapped on a Blu-ray disc" you can possibly find. Absolutely shameful video presentation. This should have never been released this way. Sadly it's still ever so slightly better than the DVD and the only way you get the proper theatrical cut with lossless 3.0 stereo. This is still the best source we have for the film.

Included in the Complete Kubrick box set with FiM encode of the same master from the Universal release without the filtering.

DTS:X mix on Universal 4K Blu-ray most closely approximates original surround mix

Criterion DVD and Universal 4K Blu-ray has additional features not found on the Criterion 4K Blu-ray