Its a fun movie. If you don't know anything about Superman's lore, and are not a comic book nerd you'll have a lot of fun.
However if you are a super big fan of comics, there are a lot of issues. It just felt like James Gunn didn't know the material or didn't care about it. It feels like they could have paid a little bit more attention to the details especially since it's supposed to launch the new DCU.
The characters are all a little bit off and it doesn't feel like it was written by someone who knows the comic material or did a lot of research. And I'm not suggesting that it was incompetence I just think he didn't care and this was the vision of Superman that he had and that goes for all the other characters.
I really disliked Lex Luthor. But I was a fan of the comics and this adaptation made him seem more Manic and less evil mastermind.
I was a little bit disappointed. It's still a fun movie. It is campy, it's full of little jokes that sometimes fall flat. Krypto steals the show, I honestly think I could have watched the whole movie about that dog getting into trouble and I would have enjoyed it a little bit more.
3 outta 5. Not great, not terrible. As fun as it is forgettable. If this wasn't launching the new DCU I probably would have given it another half star for it being entertaining but if you're launching a whole new universe off of this one, well it was no Iron Man.