...I liked it!
Man of Steel is a science fiction movie, more than a superhero film. And a pretty good one at that. A fun ride. Felt like Superman filtered through the grittier sensibility J. Michael Straczynski brought to Supreme Power, his take on Marvel's Superman analogue Hyperion and other Justice League inspired "heroes". It is a "darker" take on Superman's origin story, but no grimmer than the first couple of X-Men movies.
It is massive in scale, epic in the amount of destruction displayed, and an admirable attempt at answering the "What if?" of how the world of 2013 would handle the appearance of a powerful alien among us. They do a pretty neat job of that. Felt so contemporary to me that it was a little jarring when someone first calls the city Metropolis instead of New York - just the briefest, "oh yeah."
Henry Cavill makes a great Clark Kent/Kal-El/Superman - his ability to convey his character's maturation and acceptance of his unique place in the universe gives weight and development to what could have been a two-dimensional role. The dialogue was sometimes too... obvious? But both Cavill and Amy Adams - best Lois Lane yet - made it work.
Don't want to spoil any plot points... but I did like the way the story was put together. If flashbacks bother you? You'll be bothered. One thing that bothered me was the overuse of shaky-cam and sudden zooms - a little hand-held goes a long way for me. Instead of making me feel like I'm watching captured action, after a while I'm just annoyed. Got annoyed a couple of times.
But overall I would recommend the movie. Pretty neat new take on the Superman story.