Elizabeth McGovern

251 min cut (Extended): Fox Blu-ray. Eagle Pictures has forced Italian subs in some parts

229 min cut (Theatrical): WB Blu-ray

139 min cut (US theatrical): VHS

Eagle Pictures 4K Blu-ray, caps

The 4K includes both theatrical and extended cuts. It's overall a solid upgrade over previous discs, but some will strongly dislike the color grading.
There are some issues with encoding and grain management.

Nic's review:

Some definitely messed with it as there’s grain management going on that resulted in magnetic, squishy grain movement. Both cuts (4K discs) are affected and it doesn’t look like an encoding issue to me as the bitrates don’t drop down to single digits á la Paramount or StudioCanal. During opticals, the lowest I’ve noted on the Extended 4K was around 30 MB/s vs. ~5 MB/s more for the theatrical cut.

Darker scenes are mostly (but not always) better but when it gets brighter, particularly in exteriors or scenes like the Jennifer Connelly dance scene at minute 38, I can’t unsee the digital tinkering as it does some damage texturally.

I compared it with the Eagle Pictures and Warner Bros Fox Blu-ray of the extended cut and they all look fine without grain management like that. Eagle Pictures’s Blu-ray is an older one if anyone’s curious and credited to another authoring house than 64Biz, which did the 4K.

Other than that, except for some encoding-related chroma noise that peeks through in the DV layer, Eagle Pictures did everything right. They corrected the framing to 1.85, kept the original English titles, the English restoration note, subtitles, HDR/DV is gentle and respectful of the source black levels are better than on the Warner Bros/Fox Blu-ray. Without that grain management, this would’ve been the all-timer release we all longed for.

251 min cut: Fox Blu-ray (24-bit, Eagle Pictures is 16-bit, not audible)
229 min cut: Warner Bros LaserDisc (missing 2 minutes, but original mono mix was never released on DVD/Blu-ray)

Extended edition adds scenes cut from the theatrical, but from a much lower quality source. It's intended to approximate the original cut, but to what extent that is true is debatable.
US theatrical cut is infamously bad, was panned at release and never re-released on home video.

Both come from a 4K scan of a 35mm film out which was made from the original 2K DI but the Lionsgate release has visible dust and damage marks while the Universal release is cleaned up more thoroughly. Both releases suffer from DNR which seems to have been baked into the DI. The colour grade is basically the same for both releases but the Lionsgate has Dolby Vision whereas the Universal is HDR10 only. The compression on the Lionsgate UHD base layer is apparently fine so the FEL doesn't make much of a difference.

The Lionsgate UHD has Dolby Atmos whereas the Universal UHD has DTS:X. Kick-ass was originally released with a 5.1 track which may be on the Universal Blu-ray.

The Lionsgate UHD is on a BD-100, the Universal UHD is on a BD-66.

The Universal UHD has no extras.