I just had my my second attempt to get through this having tried months ago and only lasting about an hour with failed plans to go back to it. I haven't seen Justice League since it came out, so I don't remember it well enough to say exactly what extra scenes this has/has omitted, but damn, it's way too long. I mean, you don't see Superman until 2hrs 40min into it. However, given its extra running time, it does allow it to include more scenes from everyone, particularly The Flash and Cyborg, so it doesn't feel as rushed as the original cut.
Batman feels out of place and useless in this unrealistic world with these amazingly powerful friends and foes. He still does some important acts to assist his League, but he doesn't feel required apart from the act of helping them get together in the first place.
The main issue with this is that the fighting scenes aren't very interesting, the villains are boring, and the CGI/green screen is overdone and seems incredibly cheap. The movie just isn't very good to look at because of this. Why does it look so ugly? This version does nothing to rectify those issues. For such a long film, the Justice League members never get very close or build much of a relationship apart from the odd quips. Aquaman feels like he was tacked on in a rewrite.