On the whole, it was... okay. I really wanted to like this movie. There was some good stuff in it. The visuals were, as expected, pretty spectacular. The fight against Doomsday felt like the Zod fight from the first movie, in that you could really feel the super powers of the combatants, including the welcome addition of Wonder Woman. The cast delivered a pretty solid performance. Batman felt like a detective, Lois Lane felt like a good journalist, and I quite liked Jeremy Irons's snark as Alfred. Gal Gadot's so hot, and she's a pretty convincing Wonder Woman. Even Eisenberg's Luthor, while unorthodox, could work if you just tried to forget he's portraying Lex Luthor. They got the scheming and "hates Superman for reasons only he himself understands" part right, at least. The exploration of issues like how the world would react to a superpowered alien, how Clark himself would try to figure out what he's supposed to do, etc, these are interesting topics for a movie to delve into. Oh, and I liked the references to the comics. Dark Knight Returns is the most obvious one, but there were some nods to Injustice too.
On the other hand, right from the start, the movie tells you it's not going to respect the source material. "Hi, I'm Jimmy Olsen, photographer... and I'm actually a CIA agent who's going to be killed off right away." Superman apparently hasn't learned not to kill people yet, because the first person he fights in the movie gets sent through a wall. Batman's fighting style is strongly reminiscent of the Arkham series, which is good, except he's also very gun-happy and kill-happy. Also, his suit is apparently made of vibranium. I also think it's a bit of a pity that they've wasted Doomsday in this movie. Doomsday could've been an interesting villain for another movie down the line, but they used him up here as an excuse for a superpower battle.
And holy crap, who thought this running length was okay? There's so much you could've cut from this movie. Every Batman dream sequence could've been cut, and nothing would've been lost. Most of Eisenberg's ramblings could've been cut or simplified, and the movie would've been much improved. The stuff about the other metahumans felt pretty unnecessary too. They could've just gone down the Marvel route, and added a reference to other metahumans in a post-credits sequence.
Finally, Mercy Graves is hot and I wish she was in more of the movie.
All in all, it's got some good parts, but these good parts do not a good movie make.
EDIT: A few more thoughts:
I did like the Batmobile sequence, it showed Batman's awesome car-fu.
Superman apparently thought that when he needed to explain stuff to Batman, it would be a good idea to talk as slowly as possible. Idiot.
Superman should've, by all logic, killed Batman several times over in their fight. He hurls Batman insane distances, sometimes through walls. Also, when Superman threw Batman through that wall, it would've been hilarious if Batman had made a bat shaped hole.
What was Luthor's plan for after Doomsday kills Superman? Just leave the super-destructive unkillable monster to its own devices? For someone so smart, this seems like a rather large oversight.