Saw this the overday and though it is heads and shoulders above Superman Returns, it to my mind still doesn't touch the '78 version. It is certainly enjoyable and there are good qualities about it, it just also has many flaws. Cavill is fine as Supes, way better than Routh(but thats partly because SR sucks so much) but nowhere near Reeve. Costner and Crowe are great and the Fiora chick is badass, as well as Meloni as the Col., but the rest of the cast is forgettable.
Also, I had a hard time believing that this Superman would care that much about humanity. I get that they were going for a more brooding and angsty film, but a childhood filled with ridicule and ostracization generally doesn't leave you with a good disposition towards those who were doing that to you. I realize the Kents were there to counter that, but it just felt hard to buy.
My biggest problem with this is its just pretty much forgettable, there's no really "oh shit" moments. The action gets to be a bit montonous, nothing really affects any of them. That said, lots of action is much more enjoyable than lots of boredom aka Superman Returns.
As for the "twist", if you know your comics, Supes did it in them, so not much by the way of surprise.
Having said all that and bored you to death, it is a fun movie, definitely enjoyable, here's to hoping the sequel can have a bit more soul.