I gave it a 6.5/10 the first time I watched MOS, because I went in thinking it would have a complex, mature, and rich in character development story and I did not get that.
I gave it an 8/10 after the 2nd viewing because I went in knowing it's more of a popcorn action adventure movie.
I went in expecting something like TDK (a crime drama with a lot of themes and depth mixed with some cool superhero action) and got the Avengers (action adventure movie with some dramatic moments), 2 movies I gave 9/10 for different reasons.
The reason I gave MOS only 8/10 is because some of the dramatic scenes were awkward and too melodramatic. It also lacked wit, charm,and a sense of humor.
But if we're talking about action adventure science fiction spectacle, it's the biggest one Ive seen in my life. It's so re-watchable because of how epic and awesome the action is.
Go to this movie expecting Death of Superman or Superman Earth One
instead of the cleverer ones like All Star Superman, For all Seasons, or even Alan Moore's stuff.