The short answer to what I don't like is that this movie is a facsimile of Batman Begins with Superman instead of Batman. Too grey, too morally ambiguous for this character.
The whole point of the Kents is that they humanise Kal-el, and instill in him the morals that make him a hero, and that is what makes him a Superman. In this movie Martha does...nothing, and Jonathan actively instills the DISGUSTING idea that "you should let a bus full of school children die so you can protect your secret, the secret you actively spend your whole life revealing to everyone anyway". The end result of this is 1) a Clark Kent who watches his father die saving a damn dog when he had the power to stop it and CHOSE not to, and 2) a Clark who will murder a villain, and oddly seem more emotional at this than at any of the damage or death caused by said villain. :S
The action is loud and mind numbing, FAR too long. Again, Superman can't really be put in "danger" per se, so watching him get punched or shot over and over means nothing. There is no tension in a fight where the guy cannot even be wounded. Superman action scenes have to revolve around others for them to work. This is Transformers explosion porn nonsense. Just putting lots of "cool" scenes on screen doesn't do anything. As said earlier in the thread, there is too much action and not enough reflection of the action. I don't like comparing franchises because it leads to juvenile fanboy arguing and such, but the Avengers for instance made sure to humanise the victims of the invasion, and make it clear the heroes actually cared. Given this film had more violence, destruction and implied death than the Avengers, what do they do for the sequel? Will Superman start throwing moons at people?
Too much time with Krypton. Jor-El is not the story, and neither is his planet. Obviously having a big star like Crowe meant they felt the need to write entire chunks of the movie for him when the character exists only to give exposition to Clark, and thus us as well. The entire opening sequence of 20 minutes or whatever could be removed since Clark learns about the events when we are all told AGAIN a play by play of the events we had just seen.
The current obsession in Hollywood for shaky cam action and filming is just awful. Not just in Man of Steel to be fair, but it sucks everywhere. I also noticed that they used the Battlestar Galactica trick of "shaky cam from a distance, then a quick zoom on a moving object" thing. Most of the flying scenes were good to me, quite fun, but that was overused.
I have numerous minor quibbles, the lack of reason for the suit, just "here's a blue and red suit no-one on Krypton wore, so wear it", or the non-linear stuff which I rarely like, or the "Zod and crew come from Phantom zone, so they must be sent back there to defeat them" which we've already seen in a Superman film. I had thought they were taking a nice risk, which I liked a lot, by dispensing with the fake Clark Kent persona, since EVERYONE must know who he is based on the events of the film. But then they went ahead with it right at the end? :S He wasn't even wearing his glasses when he arrived at the Daily Planet? His face will be the most known on Earth after these events.
But in the end, it just feels like a missed opportunity. Like the people who made it don't really get Superman. He is supposed to be morally unshakeable, and it's NOT boring if done right. Being moral should be the hardest thing to do, killing should be the easiest. Any chump can kill. Having the power to, but choosing not to is much better, more heroic. What's heroic about snapping someone's neck? That's why Superheroes are SUPER heroes. He couldn't find a way of stopping Zod's oddly James Bond laser-esque slow motion attack on that wall? Perhaps the super speed he never seemed to use on ground?
No, just wasn't impressed in general. It's better than Superman Returns, but like Routh, Cavill wasn't given the script and film he needed IMO. Both guys wasted in the role when they could have had so much more to work with.