Finn Zirzow

The 4K discs in both Criterion and Imprint sets are FiM encodes, but low-passed. The compression is better, but some of the grain is lost. Difference is pronounced in screen caps, but not likely to be noticed during playback, without a reference to compare it to. Comparisons

All discs use the same source transfer. It's not of the highest quality, and it includes some slight distortion, looping, clicks, pops, and hum. Criterion cleaned it up for their release, but unfortunately also lost a lot of fidelity in the process.

MGM NTSC DVD doesn't seem to have some of the more prominent distortion and has slightly different EQ but is otherwise the same.

The Criterion Complete Kubrick and Imprint 1953-1957 sets include remastered BDs. All standalone releases are from an earlier master.
Arrow UK Blu-ray has an exclusive isolated score & effects track. Kino Lorber and Imprint have an exclusive commentary each.

Paramount 4K Blu-ray. See caps
HDR/grading: nice, but some blown out
Encoding: inconsistent, smeared motion
DNR: inconsistent, frozen
Old Paramount Blu-ray is arguably a solid alternative choice

Paramount 4K Blu-ray mono is different version of the Blu-ray mono from the same old 2000 DVD transfer.

The 5.1 remix on the 4K Blu-ray is an appalling remix done by going wild with artificially generated stems from Park Road Post who were given the surviving mono to separate. The experience is jarring and fidelity to original mix in terms of level balance, directionality and impact is nonexistent. Not only does this sound painfully weird, but the Paramount mixers then did whatever they wanted in terms of LFE, sound pans and effect changes.
The original mono mix was not restored and still needs it badly. The 4K master is filled with frozen grain examples coming and going plus some HDR issues in addition to the usual Paramount problems. It is simultaneously better and worse than the Blu-ray master.

An undeniably significant improvement from the BD yet still severely flawed. See DFIC's review.

WB Europe 4K Blu-ray slightly better encoding than Criterion (caveat: missing Criterion extras)