IM-1 is still the best of the series. As for this -- call it "shallow action fun".

Rating: 4/10 (8 May 2013)

Let's start off with saying I really liked IM-1. It was one of the better superhero movies I've ever seen. This is a sentiment shared by most of my friends.
IM3? Let's say it was enjoyable enough to watch as an action flick. However, it failed to impress me in any of the ways I would hope a major feature film would. For instance, the story. OK, granted, not all movies, especially action movies, have to have a great, let alone deep, storyline and script with sensational dialogue. It all depends what they are TRYING to be. That's where IM3 fell short, to me. It seemed like it was trying to seem deeper and more intelligent than it was.
Let's make that clear, right now. No matter how much you may have enjoyed this film, it's neither "deep" nor "intelligent". Any thrills derived are more along the lines of action and shallow motifs.
IM3 seemed to give us a number of elements just for the sake of handing them to us. The most infamous of these, what they did with The Mandarin. I won't get into that, here, in this review. But let's say the "twist" was more a twist for the sake of the twist. It was not innovative or clever. They could easily have pulled off the same plot device with any other number of names or new characters. Instead, by dropping the name The Mandarin, they slapped the faces of everyone who were familiar with this character from the comic book and wanted to see him brought to life.
Another cheap-trick element was Tony's emotional issue (again, not discussed here). You can't just drop something like that in to a character like Stark without working it in, with purpose. Otherwise it seems random and just "thrown in for the heck of it".
I'll also mention the ending, which left us wondering "why DID he do that?" Just for the sake of a few pyrotechnics and a feeling of "starting fresh". Sorry, sometimes a theme needs to make sense.
That leaves us with is not bad. Not great, though, since the Extremis characters were just a bit too over-powered (and not consistently, I might add) and a far different battle than what I might have hoped for. RDJ, of course, is masterful as Tony Stark, and he was the best part of the movie. I just wish Stark, who is one of the more interesting characters in the Marvel movie franchise, was better-used in this installment.
It's interesting to note that, while there were minimal moments of pure dialogue, they seemed slow and to drag. This is indicative of the quality of the writing and characterization, since I usually love moments of meaningful dialogue, even in an action movie. I guess this wasn't all that "meaningful". Hmm.
I leave you with the notion that if you want to just see an action film, you may, indeed, enjoy it quite a bit. Just don't set your expectations too high. Take all the elements with a grain of salt. They seem to be geared towards a more juvenile audience than the average comic book reader (yes, I meant that as it sounded).
IM3 has its moments, and is worth a view, but it's far from great, if you hope for any meat with your cheese.