This film has pretty much no surprises but is good for what it is.
Robert Downey Jr makes Stark his own, and it's his charisma and humour that really carry the film. The suit is good too, and the fights. The plot is both shallow and easy to ignore.
As an interesting note, this film lacks any shaky fake hand held camera work. The fights are traditional, and you get to see everything happening in it's full glory.