...I really hated that the Mandarin wasn't a real terrorist. He didn't even need the 10 alien rings, but damn, what a letdown!
I hated Extremis in the comics. I'm glad that Tony doesn't have the armor coming through his pores like he does in the comics and that the movie expanded on his summoning his armor by remote control (and trying to perfect it) as was introduced in Avengers.
Tony getting knocked around while working on his inventions is always a welcome scene. Crotch armor!
Also, there wasn't a lot of full-on Iron Man in the movie. Reminded me of Dark Knight Rises where there wasn't a whole lot of Batman. Heck, War Machine was mentioned a few times and I was hoping that Rhodey would have suited up in that armor once again at the end.
I don't think Tony is through with being Iron Man, but he won't ignore Pepper and shut himself off in his facility anymore. At the end, he hauled off the Jarvis mechanical arm.
It was nice to see Banner at the end of the credits, but the scene didn't allude to Thor II or even Cap II.
Tony got the shrapnel pulled from his heart long ago in the comics. I liked that he finally did it in the movies too.