It is the best Superman movie ever. So good that I came out of blogging retirement to write this review because of the negative reviews I've seen so far. Man of Steel is like a sci-fi Greek myth except that with CGI we can watch the battles instead of listening to a chorus sing about how epic it was.
First a couple of rebuttals. Some of the reviews complained about how it's difficult to relate to Superman and that the tone of the film was too serious. Let's tie these two together shall we? Of course Superman is hard to relate to. Not only is he an alien, but he's better than you in almost every way. In addition to being physically superior, Superman is morally better than you. I know preachers and priests who wouldn't turn the other cheek that many times. Furthermore, most people who walk away from a fight do so out of fear, not righteousness. Superman could kill all of them in multiple ways instantly, but he doesn't because he's better than us.
This leads us to the serious tone of the film. The movie is serious because a handful of aliens is threatening to end life on the planet. That's some heavy shit. I don't need Will Smith and Jeff Goldblum cracking jokes. I need a superhero who will take care of that. Otherwise, we are all effed. Aside from that, Superman is serious because he just met his biological father and discovered that none of his race exists any longer. When you realize you are the only alien on the planet and little hope of finding any others, that's probably a low point in your life. To top it off, that pesky moral center of yours is reminding you that you should be helping everyone even though it may not be in your best interest. That is also a pretty lonely place to be.
My next rebuttal is for those who thought Man of Steel was missing some romance. If that's what you came to see in the Superman movie, well, "I'm sorry ma'am, but you're in the wrong theater. The other Amy Adams movie where she's planning a wedding and her fiancee gets killed in Iraq but then she falls in love with a rough around the edges but has a heart of gold Irish fellow comes out in the theaters next month.
Finally, I'll say that the film has a great story, is full of action, and manages to make Superman cool again. More importantly, it sets the stage for a Justice League movie. Now that Superman has come forward and revealed himself to the world, hopefully other superheros will do the same.