Polly, after reading your review, I'd pretty much decided not to go see Justice League at the theatre...but after three days of just doing stuff around the house, I needed to get out and sit in a dark room and eat popcorn, so I went early on Sunday afternoon. Glad I did, as I really enjoyed the film.
No, it wasn't nearly as much fun as the first Avengers movie, but Marvel doesn't always hit the mark, either. (The second Thor film literally put me to sleep, and Dr. Strange was poorly put together.) The first half of Justice League was especially good, I thought; the battle on Themyscira was breathtaking, Bruce's meeting with Arthur Curry was amazing, and Wonder Woman was - oh, well, she just was! ("Minimal"? I thought she was in more scenes than any other character.) One of my favorite scenes was later in the film, when she uses her lasso on someone without their knowing it - THAT was funny!
The big final battle royale was dark and somewhat cartoony - it always is - but it was relatively brief compared with most movies of this type.
One surprise was the final "easter egg". There was a brief one about thirty seconds into the end credits, but then I figured that was it. I started to leave and realized that at least a dozen people were still seated, and I thought "They're just confused and think they're at a Marvel movie". I hung around anyway, just to be sure, and damned if there wasn't another egg at the very end, a la Marvel. Is this the first one they've done that with? I like it of course. I still laugh whenever I think of the shawarma scene from Avengers.
My bottom line: best DC superhero movie ever that didn't have Christian Bale in it.
Whoops, except for Wonder Woman, of course.