Cutting to the chase, I like this movie much more than the average critic. It only scores 28% on Rotten Tomatoes. The biggest problems with the film are that it spends a very long time on setup, you almost need a roadmap to follow its multiple storylines, it is intensely violent, occasionally brooding, and the payoff is overloaded with special effects. However, I like the payoff, and I think that when the story is not being overly convoluted that there is a richness to it. There are many emotional moments that go by quickly, but they work if you are paying attention. Due to the complexity of the film, you really have to focus to keep up, but I like a movie that engages the brain.
Many people did not like Jesse Eisenberg as Lex Luthor, because he is not the typical intellectual scheming Lex Luthor. He is more manic, like a mix of Lex Luthor and the Joker or the Riddler. However, I think that Eisenberg's manic performance here is fantastic. Some of his dialog is the best in the movie. His character is key to the entire film.
Portions of the dialog with extra characters seem overly simplistic, which is an annoying trend that I have noticed with other superhero movies.
The "Ultimate Edition" adds 30 minutes to the original runtime, making it almost 3 hours long. However, the Ultimate Edition restored scenes and storylines taken out of the original for time. The result is less confusing and richer in detail.