Justice League shows that while DC is learning from the Marvel MCU what makes a good ensemble movie, they still don't have it. Unlike Suicide Squad, which I liked, I couldn't decide if Justice League was more bad than good. It is mixed -- definitely better than the Batman vs Superman which was just bad -- but it sure isn't great. There are good touches of humor, and the use of The Flash as comic relief is well done. But over all Batman, Wonder Woman, and Cyborg's brooding over their own mini arcs trip over each other and get in the way. Marvel manages to have more characters in their ensemble movies and manages to give more of them better story arcs than this DC offering.
So was it bad? No.
But was it good?....