While its nice to see Robert Downey Jr in something other than a mug shot, this film plays to the dumb crowd. I guess if you can suspend your disbelief enough to accept that a man can fly, you can look over all the other little things that are wrong with the picture. An Air Force officer would never be as close to a contractor as depicted in this movie, there are laws against that. The impacts Downey suffers in the first suit and while testing the second surely would have killed him. Etc...
Then there is the issue as to who the bad guys are. His company has been selling weapons to "good" guys as well as "bad" guys but you never really get to know why they are bad other than they push civilians around. When he finds out that his board of directors are the ones who pushed to sell to the bad guys, what does he do? He goes after the "bad guys" instead of his board of directors.
On a plus, Paltrow looked pretty good. I don't recall seeing Samuel Jackson in it at all.