+++Warning, this contains minor spoilers from the movie+++
The theatrical version of Justice League was released in 2017. It continues the story that started in Man of Steel, and is the direct sequel to Batman v. Superman: Dawn of Justice. Ben Affleck, Henry Cavill, and Gal Gadot return to reprise their roles as Bruce Wayne/Batman, Clark Kent/Superman, and Diana Prince/Wonder Woman. The new heroes introduced in this film are Flash (played by Ezra Miller), Aquaman (played by Jason Momoa), and Cyborg (played by Ray Fisher). Many of the supporting cast members from the previous films, including Amy Adams, Jeremy Irons, Diane Lane, Connie Nielsen, and J.K. Simmons, also appear in this one.
The theatrical cut of the film is definitely a mixed bag. As many are aware, during post-production, Zack Snyder had to step down due to a death in his family. During that time, WB decided, instead of doing a Justice League trilogy of films as Snyder envisioned, to make this a stand-alone movie. They brought in Joss Whedon to complete the production, which involved removing several story elements and conducting reshoots that significantly altered the overall storyline. After the tepid reception to the film by fans and critics, Whedon was blamed for ruining the movie, and indeed, his additions range from chuckle-worthy to downright stupid. There was, of course, his on-set behavior that was leaked out by Ray Fisher and later confirmed by Gal Gadot, which then caused an avalanche of accusations about him going as far back as when he was working on Buffy The Vampire Slayer and Angel, and pretty much ended (for now) his career. However, it is clear that Warner Brothers really was the entity that fucked up this movie, and caused a version of the movie that was totally out of place with the movies that had come before it was released.
As mentioned above, Zack Snyder had intended for Justice League to be a three-part story, with this movie split into two parts (which he essentially got to do with the Snyder Cut of the film four years after the theatrical release) then a third movie set in the nightmare world that was teased in Batman v. Superman. However, when Snyder had to step away from the movie, Whedon was brought in to cut the running time and make it a stand-alone film. The result is a mishmash of Snyder's story with Whedon's additions (mainly to add humor, as WB thought the DC movies were too dark and wanted to infuse some of what worked for the MCU into their movies). For the most part, the theatrical version is stuff Snyder filmed, with some changes like tweaks to the battle with Superman when he is brought back to life, Lois' role in the movie, the race between Flash and Superman at the end, and the really dumb subplot of the family living next door to the contaminated nuclear reactor (which was a fictional Chornobyl) who (for some reason) did not leave the second the aliens showed up. The biggest change in this version is Steppenwolf's arc (as well as his look), so a lot of his dialogue ended up changing. And, the post-credits scene was quite different than the scene that came at the end of Snyder's version. But what Whedon cut was far more substantial than what he added (which is why Snyder still got the directing credit).
The 4K set is a two-disc set containing a UHD disc and a standard blu-ray disc. The A/V quality is outstanding, and the film looks and sounds wonderful in the UHD format. The UHD disc only contains the movie itself, and the standard blu-ray disc includes the movie and bonus material. The bonus content includes multiple behind-the-scenes features (clearly shot when Snyder was still on set, as Whedon was nowhere to be seen), deleted scenes, and a gag reel. There are also some featurettes on how the Justice League has evolved from the comics to the various animated series to live-action. It is a decent amount of material for those who like watching the bonus content.
Overall, the movie is not as bad as its reputation suggests, but it was definitely not as good as the movie Snyder intended to make. I still think WB/DC would have been better off establishing the main characters through solo movies first, as was done with the main heroes in the MCU movies, then bringing them together for the big team-up. However, diverting from what Snyder had set up made the problematic DCEU even worse, as this movie feels out of place. Ultimately, it is worth watching if nothing else to compare and contrast with the Snyder cut of the movie, but it is not a film that needs multiple viewings.