Finally got around to seeing this, lengthy'ish review coming...
Summary: Everything about the movie was good except the Directing, Zack Snyder should be fired without pay. Affleck as Batman was terrific, Gadot's Wonder Woman will have you excited for the WW movie, Eisenberg made a surprisingly good Lex, I even thought Superman was much better in this one.
First 30-45 minutes of the movie: This isn't terrible. I'm intrigued. It's a bit all over the place, and DC will have to do much better than this to compete with Marvel, but this has potential. I'm not sure what all the complaining is about.
Next hour and a half: Ok what in the world is going on in this movie?? This is completely unorganized. Clark Kent is at work, now Batman is having a vision, now Lex Luthor is talking about God-knows-what, now Batman is doing some science stuff, now Superman is in a bathtub with Lois, now Batman is working out, now Superman is saving a family from a rooftop, now there's this girl who will obviously be Wonder Woman, now Superman is saving someone else, Batman is having a vision again, the State Senator can't make up her mind, annddd another Batman vision. I'm some terrible combination of bored and confused at this point. Again.... fire Snyder immediately.
Final 30-45 minutes: This has actually gotten really good, surprisingly. The Batman/Superman fight was great (although the way the fight ends was kind of "meh"), Batman just took down 24 guys in a warehouse within about 30 seconds in what was easily the best scene of the movie, the final fight against the giant god-like "Doomsday" is very entertaining and Wonder Woman is stealing the show (she's as good of a fighter as she is absurdly hot), Batman is also holding his own against D-day with his quickness and ability to outmaneuver him instead of trying to slug it out. Great finish to the movie. Very redeeming.
Ending: So-so. Not a bad setup for the future. I'm still very intrigued to see what DC brings to the table. Not the best start, but good enough that I'm ready for Suicide Squad and the latter films.