This film is much, MUCH better than the theatrical cut, but it does have some problems.
Getting the negatives out of the way, it can feel a bit long or bloated(mainly due to slow-mo, and a lot of it). Some of the CG, while really good, while other bits are very much not. While I like a good chunk of the soundtrack, other bits I was indifferent towards.
But that said, this is a straight up epic. Characters like Cyborg, Flash, and Steppenwolf are more fleshed out and far more interesting than their theatrical counterparts. Every scene feels like it has a purpose within the story, and we actually come to care for the characters, despite the similar premise. The action is of course phenomenal, but it is Zack Snyder.
I really hope that this gets a sequel, especially after the epilogue. Love or hate his style, Zack Snyder's Justice League is HIS movie, and his movie turned out to be nothing short of miraculous and heartfelt.