Finished the Snyder Cut. It was about what I expected - I preferred how the theatrical version handled Batman and Superman (aside from a few scenes that were in trailers but not in the theatrical version), and I VASTLY preferred how the extended version handled Cyborg (who felt like a completely different character) and Steppenwolf (who actually felt like a character).
The nightmare future scenes seemed like trailer bait (among other things, the Joker doesn't actually say "we live in a society", and they're entirely visions or dream sequences), but while I'm not super familiar with DC, the inclusion of characters like Iris West (though I don't recall her being named), Ryan Choi, Martian Manhunter, Darkseid, Desaad, and Granny Goodness were great from my perspective, so I can't imagine how exciting they'd be for people who are actually familiar with those characters. I felt like it probably could have been trimmed down to three hours, though.
The only thing that stood out to me by its absence was the conversation between Batman and the Flash about telling the Flash to focus on saving one person at a time - it felt like a good moment for Batman, making him feel more like a mentor.