So I went to see Iron Man 3 yesterday. Loved it, but if you'll like it or not might depend on your expectations for an Iron Man movie. First of: the trailer is a bait and switch, and by that I mean that it's a lot less serious than it seems like it is. It's more of a comedy than the other films were and even kind of similar in tone to Kiss Kiss Bang Bang, a comedy also directed by Shane Black that features Robert Downey Jr. as the main character. Also, go see Kiss Kiss Bang Bang, it's incredibly underrated.
Anyway, it should also be noted that there's not a whole lot of Iron Man in Iron Man 3 and a hell of a lot more Tony Stark. So you'll like this movie if you like Tony Stark.