After the horrendous original Justice League movie, it was pretty wise for any DCEU fans not to expect anything drastically marvellous from the Snyder's Cut. There were a lot of plot holes in the original Whedon version, which was not about the heroes who came together to save the world but more like they were united to reincarnate Superman, who would win the battle for them. It was dull, with absolute ordinary CGA effects and minimally exciting.
But the Zack Snyder has made the best out of the situation. One may argue the length of 4 hours and 2 minutes is exactly a viable movie watching time but let me tell you, it could have easily split in two different movies. Every character has their own history often revolving around lot of emotional attachments (we know Snyder usually does that) but the main aspect is every character has their own significance in this film. They have huge climax defining roles so that audiences do not feel bad for anyone. Unlike the original JL, this isn't all about Superman rescuing the day.
Also, the visual effects are really staggering. Snyder presents battle scenes in a slow motion at times, leaving the audience off their seats more often than not. The fight scenes are more frequent, lengthy and epic. In a nutshell, this is the best version of a Justice league movie until this date. The film ends with a lot of cliffhangers where characters from Arrowverse pop in Batman's (Ben Affleck) dream, which almost feels like a premonition as mentioned by the character. Hence, the director had left something for the future, would the productions want to continue the story.
This version of Justice League gets darker with time, Snyder racks tragedies upon tragedies during the build up of the characters. But still, the scenes are intensely dark which is more enjoyable. The dark themed background music really helps to connect with the viewers, hence, totally different from the original version which was nothing more than a sleeping pill.
I would rate this movie 8 out of 10, considering how disastrous the original panned out to be, which kinda worked both in favor and not of Zack Snyder.