Hmm, I really enjoyed the first one, and it seemed universally well received so I did not think much more of it.
Speaking as someone who has been a long term comic fan and has read Captain America for the last 25 years I thought that they caught the origin perfectly. The way they made Chris Evans look so skinny and weak, and then had him transform into Cap was a masterpiece.
For me this was the first time that Marvel began to bring all the bits together that was laying the groundwork for the Avengers.
The trailer for the Winter Soldier is superb, whether the original was a movie that was liked or not, it looks better. There is a sequence in the trailer (with the SHIELD craft) that looks out of this world.
My only complaint so far is using the Winter Soldier so soon. I would have liked a movie or two with the legacy of Bucky as an emotional heart of the films (perhaps with references to a Russian super assassin in the background) before the Winter Soldier appeared.