Finally saw Winter Soldier (yes I know two weeks after release). I do it mostly to avoid over-crowded theatres, and it was a bit of an unpleasant surprise when it was almost full.
After viewing it, I think I understand the reason. The hype is actually right this time. The film is basically one big "wow" from beginning to end, and I mean it in a good way.
First and foremost the action scenes were stunning and really served to demonstrate the "super-soldier" aspect of Captain America. One aspect of Captain America from the comics that both the first Captain America film and the Avengers downplayed is his sheer agility -- an ability that allows him to tangle with the powerhouses -- and this movie does a wonderful job demonstrating it. The fact that they picked Winter Soldier as the main villain allowed Cap to demonstrate the upper limits of his potential since he is within the same weight class as Cap, unlike Loki from the Avengers, which, frankly, made Cap look a bit useless in the first film due to the disparity in their respective powerlevels.
Thematically the film is a lot darker than your average Marvel film, and surprisingly it actually worked in this movie's favor. I think the main reason for this is that Winter Soldier, unlike Man of Steel, focused a great deal more on characterization and uncovered a lot of "skeletons" in the characters' pasts. The emotional scenes are also well done for a comicbook flick.
*****Spoilers Ahead****** Steve's meeting with an older Peggy Carter is actually touching, as with his flash backs about Bucky (a.k.a winter soldier), unlike the irritating flashbacks in Man of Steel and Wolverine. I think the main reason is that they actually help the viewers relate to Cap instead of providing simple exposition, as in the case of the previous films ******** End Spoilers **********
Over all, I think the only gripes I have with the film is the death fakeouts. It is a lot less effective when you realize how some of the characters have long term contracts with Marvel. Let me put it this way without giving away too much. The first time a main character gets shot and is presumed dead, the viewer still takes a while to recover from the initial shock of it. But when two other main characters are set up for dramatic deaths, the viewer can't help but roll his/her eyes because seriously, is the director really going to kill them before Age of Ultron is out?
I think that this film is the best in MCU so far. Yes, even ahead of Iron Man and the Avengers, which I felt are a bit over-rated and in the case of the former, catapulted to greatness by Robert Downey Jr.'s performance. Hope Marvel Studio keeps it up with Guardians of the Galaxy.