Just seen it. No spoilers:
I think it has been unfairly treated by the critics; it's a fantastic action-romp. Affleck is a fantastic Batman, Eisenberg plays Lex with pschotic glee and Cavill is good as Supes.
There isn't much of a plot but there are so many epic moments in this and the action is very well done. It is very serious though, with only a few moments of levity. It's mostly set-up for the upcoming Justice League film, which is why it is very disjointed.
But all in all, I had a blast watching this! It's so great to be able to see Batman and Superman in the same film.
7/10