As for the GA reviews, it seems the biggest problem is the editing. But the performances are fine across the board, other than a few wooden lines from Gadot.
It has now been over 24 hours since I experienced the movie in the IMAX midnight premiere over here in Sweden and it's quite a conflicting film to talk about. I think a lot of people who has seen it know what I am talking about when I say that for everything in the movie that was good - there was also almost always something in the back of my head telling me why it really doesn't work as well as it should.What was apparent the most throughout the movie was the the editing is pretty damn terrible at times. Every time a scene seemed to go somewhere really interesting and I started getting invested - it cut to the next one. There's a lot of weird editing choices that takes out a lot of the emotional resonance that you're supposed to feel and I don't know if a second viewing will help me get the feel of the pacing a lot more or not. I find it hysterical that while a lot of people are saying the movie drags, I actually found myself wanting the scenes to go on for longer so I could properly take in what's happening. Now the first 5-10 minutes has its flaws in the execution too but it delivers a kick ass intro for the movie that gets you pumped to see what's about to come and while there was nothing in the movie to completely take you out of it... there's also nothing to get you invested because you never really feel the build up or that it's all going somewhere. When the two most famous superheroes are about to square off - you should be completely invested because the movie should have built up to that point... but it really doesn't. There's a lot of really good action in the movie I guess (in fact probably some of the best I've seen in a comic book movie) but it's really in service of almost nothing.
With that said, there's a lot to like. I didn't have a problem with any of the performances in the film (although Gal Gadot has some wooden line deliveries here and there) and I actually like what Eisenberg did with Lex Luthor and the way he's used in the story is one of the most interesting things about it once you piece it all together... and it would've been an absolute killer if they had just spent more time on it. Ben Affleck might be the best on-screen Batman we've ever had and there are a couple of "punch-the-air" moments which are a lot of fun. The music is excellent, the cinematography is gorgeous and the movie does have its fair share of jokes (mostly coming from Perry White).
I really want to see the extended R rated cut because I refuse to believe we got to see these scenes in their entirety. The movie has such a weird and disconnected pacing that you wonder who to really blame it on because I doubt Snyder is the only one responsible (and even if he is, the fact that no-one else noticed it before the final cut...).