FiM

US Arbelos Blu-ray (encoded by FiM) or UK MoC Blu-ray. Both are the same 4K restoration. No comparison available

Sony 4K Blu-ray and France Carlotta 4K Blu-ray (FiM encode) are similar

US GKIDS/Australia Umbrella 4K Blu-ray authored by FiM with identical encodes

UHD vs BD comparisons

UK Second Sight 4K Blu-ray is FiM encoded and superior to French Severin or German 4K Blu-ray: see comparison

Different color gradings, 88 Films disc is encoded by FiM but Vinegar Syndrome encode (by Marcus Johnson) is more than robust

Vinegar Syndrome potentially has better audio than 88 Films, due to VinSyn possibly having EQ'd the audio mix after Fortune Star scanned the track in a way that makes it sound too hot, whereas 88 left it alone without addressing that issue. However, no direct comparisons exist

Included in the Complete Kubrick box set with FiM encode of the same master from the WB release without the filtering, 1.85 ratio restored

FiM encode; BFI shows noticeable macroblocking

No dip around 10 kHz, wider dynamic range, more natural EQ; BFI & Carlotta BDs are identically worse; HMAX Streaming is similar to the BDs but has worse dynamics

Arrow has a different grade and a better encode than the Shout! Factory, though the difference in either is not major. Imprint release, which leaves Shout! Factory's master and subtitles as is, is encoded by FiM. https://forum.blu-ray.com/showpost.php?p=24473097&postcount=56

Original mix: Shout! Factory 4K Blu-ray (similar to Criterion LaserDisc, but less distorted)

Alternate mix: Scanbox Nordic PAL DVD

Surround remix: HK Video France 4K Blu-ray (5.0)

Arrow used the alternate mix, but with extra filtering and lowered dynamic range. The alternate mix has much better fidelity.

Imprint presumably used the Shout! Factory original mix and left it as is, though no official confirmation.

Arrow has a much better translation.

Arrow LE has the Taiwan Extended Cut which will not be present on the standard edition. However, Imprint is FiM and has its own archival extras not present on the Arrow.

Both will look identical in motion but the Turbine looks marginally better due to a higher bitrate allocation by each cut being given its own disc, whereas Arrow had FiM seamlessly branch the two onto one. However, Arrow has both cuts in Open Matte (on Blu-Ray) and corrected the opening Universal logo's aspect ratio. https://slow.pics/c/McvVcYDG

Radiance 4K Blu-ray from nic:

Unadvertised HDR10 grade that looks better than the equivalent Blu-ray it's packaged with, grain rendered very clean even when it's heavy. FiM encode so surely it's better than the Media Blasters UHD, but there are still issues with frame stability, some shots have this jitter that kinda hurts to look at. Not a night and day upgrade over the Blu, but it's better and despite its issues, probably the best it'll ever be.

FiM encode Caps

UK Warner Bros Steelbook 4K Blu-ray is slightly worse in encoding compared to FiM but otherwise excellent see caps

Old WB Blu-ray has exclusive extras

Umbrella 4K Blu-ray > Lionsgate 4K Blu-ray (FiM encode on Umbrella 4K Blu-ray)

Umbrella and Lionsgate releases have different extras, plus Lionsgate has an Atmos track

StudioCanal 4K Blu-ray > Criterion 4K Blu-ray. 

StudioCanal 4K Blu-ray is encoded by FiM and doesn’t have the low-pass filter the Criterion 4K Blu-ray has.

Criterion 4K Blu-ray is closer to the original DVDs than the 2015 Criterion release, not sure about whether the StudioCanal 4K is like the Criterion 4K/original DVD

Criterion 4K Blu-ray has FEL Dolby Vision, StudioCanal 4K Blu-ray has MEL

FiM encoded, 4K restoration for both theatrical and director's version

88 Films is FiM encoded

Germany Filmjuwelen 4K Blu-ray is disappointing with AI upscaling

Australia Imprint 4K Blu-ray disappointing, nice new master, but poor encode, grain completely crippled in some scenes, artifacts abound, etc, makes Kino Lorber look like FiM.

Arrow UK 4K Blu-ray > Paramount US and Capelight DE, same black crush on all three but the Arrow is encoded by FiM and has very good new supplements, the Capelight looks slightly low-passed, but in motion it probably looks about the same as the Paramount, see caps comparison for all three.

Arrow and Paramount basically sound the same, the Arrow has a slightly higher bitrate. Capelight is probably the same too but for now it's TBA.

Paramount US 4K Blu-ray has FEL Dolby Vision 

Arrow UK 4K Blu-ray and Capelight DE 4K Blu-ray have MEL Dolby Vision