Rotten Tomatoes - Audience scores it lower than every MCU aside from Incredible Hulk and Iron Man 2
Cinemascore - Audience scores it lower than most MCU as well
IMDB - 7.5/10 is only notably higher than Incredible Hulk and First Avenger. It's a bit above IM2 & 3 and First Avenger, but not blowing them out of the water.
Much like Man of Steel, it's a divisive film, pretty 50/50 from everywhere I've seen and everyone I've talked to. I'm expecting a 2nd weekend drop as well.
Personally, I want it to succeed enough to keep moving forward with their films, but not good enough to guarantee Snyder or the screenwriters are kept. I've seen plenty of people who liked it still say it was kind of messy.
On the other hand..... I still utterly hate their damn Joker design coming in Suicide Squad. -_-