Really good modeling and texturing work.
It looks pretty good, it could just be that you need to do a bit of grading, as the colours are a bit vague.
I am sure you have seen plenty of reference images, but have a look at these.
http://collider.com/wp-content/uploads/iron-man-2-movie-image-22.jpg
http://geekspodcast.com/geekpress/wp-content/uploads/2010/05/im2_2.jpg
The maroon colour is more vibrant in those reference images and while you have added dirt, perhaps add more wear and tear marks in places you would expect it to be and less dirt and dust, and you could add some grime where parts of the suit come together as in the reference images, like grooves and parts where metal come together.
While Tony Stark does get down and dirt with building robots, working on engines, he is still very well presented and clean and so is his iron man suits, so that is why I believe you should have less dirt on the suit, especially the breast plate area.
It could also be the angle, but the breast plate feels a bit small compared to the reference images. It is however apparent that you are modelling to a specific version which is not quite the same as the reference images I have added.
Modeling wise, I am sure you are done and won’t go back to it, but the gaps between some of the parts could be wider, for a lack of a better word.