I'm, er, mixed.
Look, anyone who knows me at all knows that I care little about superheroes and even less about the comics that spawned them, so taking the trailers in isolation:
-The Justice League movie looks weird. It's got this grim aesthetic with lots of quips, and Batman being in broad daylight with metahumans highlights just how rediculous it is. It's also a clear reaction to the reaction to BvS, and while that was a bad film IMO, the reasons for that were primiarly in plot and character rather than tone. It highlights what I've always felt, that Batman has no business in the Justice League, and works far better by his lonesome. Also, the slow-motion scene drags on too long. But I will say that Ezra Miller is a good Flash. Assuming The Flash TV series is indicative of the character as he appears in the source, they've captured it here well.
Also, Jason Mormoa by the sea. Is he looking for Atlantis? Because last I heard that was back in Pegasus. ;p
-The Wonder Woman movie looks a bit better. I see Jim Kirk...I mean Chris Pine, can still get the girls. It's also somehow performed the feat of getting Wonder Woman on the battlefields of WWI, struggling against machine guns and mortars, and somehow NOT making it look cheesy. This feels like the far more coherent product. Also, is that Wonder Woman's theme from BvS I hear at the end? Because if so, more of this music please.