After thinking about it a bit more after last night, here are my thoughts.
I don't know about anyone else but after seeing this movie late last night, I can't get this movie out of my head. In a good way! This movie was so different than what's come before and I'm not just talking about the increase in action.
I didn't find it too dark at all, a bit grim but it worked with the story they were telling. My only real complaints...
1. As many others have already said, they needed to let the flashback scenes breath a bit more. They were too short. I didn't want them to be as long as the ones in Batman Begins, but then again, I wonder what the combined run time for them was. BB had two major flashbacks that were fairly lengthy, while MoS had something like 4-5 maybe six but they were shorter of course.
2. This one is an incredibly tiny nitpick, and I usually don't nitpick films. I thought it was kind of weak that Jor El was able to beat up Zod. He's a scientist who was engineered to be one while Zod was engineered for battle, which I assume is war tactics as well as hand to hand fighting.
3. Too much shaky cam. This was the first thing my wife said when I asked her if she like the movie. Her exact response, "it was terrible". I thought she meant the overall film but then she explained that she only meant the shoddy camera work. I expected more from Snyder in that department as well as the visuals. Thinking back to 300, Watchmen and Sucker Punch, the scenes in those films were shot well and were clear and easy to watch. In this film he may not have pissed off some fans by putting in slow motion like he usually does, but it seem he traded that up for sloppy camera work. Don't get me wrong, I'm used to shaky camera during action scenes, that seems to be the trend this past decade but as my wife pointed out, the camera was moving constantly in stupid ways even during talking scenes where it should have been still, minus any panning they might have wanted to do.
The performances in this were great. While I grew up watching Donner's films(and those terrible sequels which I haven't seen since my grade school days and don't plan to revisit)I must say that this is my favorite Superman film and this next opinion might open the doors for people to give me a hard time, but as much as I loved Reeve in the role, Cavill is my favorite now. He edges out Reeve just a little. I really thought Costner did a fantastic job, might be bias due to being a big fan since childhood watching a number of his films with my dad. I couldn't tell you how many times I've seen Field of Dreams and Robin Hood, Dances With Wolves and No Way Out. I just wish he had a bit more screen time. Which goes back to one of my complaints that the flash back scenes needed to be fleshed out more. Amy Adams was pretty good as Lane, since I don't read Superman comics I'm not 100% sure how accurate she was written when comparing the character to the comic version, but I liked her overall. Michael Shannon was great at Zod. At first I was worried because his first few scenes in the beginning he was overacting a bit, but once he comes to Earth he was fantastic.
As for other complaints that a number of critics and fans had, I didn't give a damn that Lane knew where Zod and Superman ended up at the end of their fight. It's a nitpick as far as I'm concerned and it didn't bother me at all. The destruction of Metropolis and the obvious deaths of a lot of it's citizens also didn't bother me as much. People made it sound like Superman didn't give a damn, but he was in the middle of a heated battle and a lot of the destruction was from him being thrown into the buildings by Zod and there's not much he could have done in those moments until he got his footing back. My wife and I both agreed that since this movie was PG13 they wouldn't have gotten away with showing numerous dead bodies around, which it seems is what some fans wanted from the complaints I have read these past few days. They had scenes of citizens running away from the destruction, not to mention early on when that ship is using that gravity energy to terraform Earth, you can see some of the people of Metropolis getting lifted up way in the air along with the cars and rubble and then getting shot back down.
Overall, I give this movie a 3.5/5. I almost wanted to give it a 4 but I thought about it a bit longer and realize that it wasn't THAT good. I definitely will be seeing this in the theater again but this time it won't be 3D on Imax.
I do feel bad for all the hardcore fans that were disappointed with the movie, or even flat out hated it. Hopefully you get the movie you wanted with the sequel. As others have said, if this was the BB of the series, maybe the next one will be more like TDK and blow the first film out of the water. In certain areas at least.
One last thing. At any point in the history of the comics, did the Kryptonians make/engineer their citizens or was that made up for this movie? I really liked that idea.