The RLM review convinced me to give it a go, and I didn't dislike it. It's probably Snyder's best since, I don't know, Watchman? Still not great, but I think there may be a genuinely very, very good movie under all the excess. If someone with more discipline cut it down to 3 hours, I think that would help a lot.
Like Rich said in the video, the first half I kind of loved. I didn't expect Batman-as-warm-father-figure, but it worked and I liked it. It was also effective to dramatize each team member joining by having them show up doing an action scene, to show what they add to the team. E.g. Aquaman (no spoilers).
It falls down once they bring Supes back; as in BvS and the theatrical cut, Snyder's Superman is a black box: situations go in and violence comes out but I have no idea why or what it means. For a movie obsessed with visions and dreams, the lack of anything similar for Superman is an odd choice. Showing the resurrection from his POV, letting us see it as scary and confusing, showing what he does or doesn't remember of his death, would really help convey his motivation for going all murder machine. As-is we're expected to buy that he kills, seemingly at random, without Lois's love to soothe him. That's Snyder's Superman: savage beast, sans love.
Also useless: Martian Manhunter, all the slowmo (outside of the Flash scenes), the needle drops, Lex Luthor, the Joker, most of the epilogue after Clark pulls open his shirt to reveal the S logo, which should have been the final shot, imo.
If you watch any material at all from this version, make it the Flash's introductory scene. It's genuinely great, a wonderful little mini-movie where all of Snyder's fetishes and hangups actually work. The slowmo and needle drop are motivated, it roots the fetishization of superpowers in a real human connection, and it manages more than one tone (comedy and drama!) with ease. A great, great scene that deserves a better movie around it. (Which I would embed, but there's no copy of the full scene on YouTube.)