A little late to the discussion, I'm mostly in agreeance with overtone. Overall, it's a great story, and probably my favourite of all "realistic" movies about aliens and space. I absolutely adore this movie, and that aspect barely bothers me - mostly because the government does far more irrational things, not to mention the American government's proclivity to cover things up and deny, deny, deny
There are other aspects of this movie that get to me far more than the aforementioned part, but all in all, this movie makes pretty damned good sense, considering most sci-fi movies make little to no sense.