Just got back from watching it with my son.
I enjoyed it more than I thought I would, and it's because the "jokes" weren't as bad as I thought they would be. There is still that feeling of humanity and drama that Snyder put into his DC universe (which was also present in WW), albeit diluted here. The characters are great, I liked them all, and they work great together.
The first act was a bit choppy, but given the time constraints, that was to be expected. Second and third act were pretty solid. Steppenwolf was your average world-conquering nemesis, I don't quite understand the hate... his motivations were adequately explained in the flash-back scenes. As for the CGI, I didn't really find it bad. It wasn't breakthrough, but it wasn't bad at all.
The team worked great on screen, and the interaction between Batman and Wonder Woman was especially good. Some of the Superman-Batman interaction felt forced to me, at the end of BvS I felt they had put their differences aside. Seemed like some Whedon/WB crap to me...
Flash did get a bit on my nerves, and it was his jokes that fell flat sometimes. Maybe because of overuse... I've read some criticism because he trips, or is easily taken away by parademons, but both instances are perfectly logical in the context of those scenes and who Flash is in this movie. Aquaman was great, Momoa did great with what he was given. Batman had his moments, but I feel he's the one that suffered the most due to (what I assume to be) Whedon's re-shoots. Superman was fine, his first scene was simply awesome. That scene is pure Snyder drama and action. Later, as he slowly put on the "beacon of hope" mantle, he did seem a bit uncomfortable. I'm assuming most of those scenes are Whedon's, so I guess Cavill wasn't really at ease with him or the direction he was giving. Come to think of it, it's the same impression I had with Batman's (re-shoot) scenes. Cyborg was fine. I had no expectations with the character, and I felt his scenes with his father were very good. Gadot was her usual charismatic self as WW, and her conflict with Batman was also great.
The action was great, I enjoyed all the action set-pieces. But... they're not as strong as BvS IMHO.
Music wasn't anything special. It wasn't bad, but it wasn't inspired either. MoS and BvS have much better music.
Cinematography was good, with some dodgy bits that looked a bit unimpressive and washed out, which I'm guessing are Whedon's work, as Snyder is quite the visualist. I missed his so-maligned "moments".
The closing scene with Diana, Bruce and Alfred was great. The first post-credit scene was silly, the second is brilliant. Oh, and Batman's opening scene is brilliant.
So, overall, I think it's a good, fun action movie. Not better or worse than MCU movies. But, then again, as you all know, I'm a big fan of BvS, so all you BvS haters can ignore my thought s on this...
At any rate, I sincerely don't understand the criticism this is garnering. It's a perfectly fun and action-packed movie with some really touching moments. I can only think it really is suffering from CBM fatigue, and unfortunately, the DCEU hasn't built enough of a following to carry it through.
I do wish WB had let Snyder fulfill his vision, critics be damned. You can tell that the movie was going to have a lighter tone than BvS anyway, but I don't think Whedon's contributions really made for a "better" overall movie (and I do think that some of the "jokes" and little interactions that seem to be Whedon's are actually good). More than Whedon, I blame WB for meddling with this. Things like curtailing the running time, insisting on doing re-shoots with a moustache sporting Cavill, and getting Danny Elfman to do the soundtrack all affect the final product.
If you're on the fence, try to go and see it without preconceptions, and more likely than not, you'll spend a couple of hours having fun seeing some of your favorite heroes kicking ass on screen.