It's probably one of my least favorite MCU films. The Mandarin twist is actually good, or at least I enjoy Kingsley hamming it up as Trevor--but Killian was a lame villain, so that hurt the twist. I appreciated it trying something different (especially after Iron Man 2 was mostly whatever) but I just couldn't really vibe with it.
It's also kind of funny how little the events of the film are ever referenced in the future until Shang-Chi happened, you'd think a terrorist cell kidnapping the President of the United States--with the Vice President in on it no less!--would be a bigger deal than it is treated.
Also, without taking into account the retcon in All Hail the King, what was the status of the Ten Rings organization supposed to be in Iron Man 3? At face value, the Mandarin was fake, but Iron Man 3 never wrestles with the fact that this implies the Ten Rings were entirely staged as well, despite them being very real in the first Iron Man.