One of my friends at work finally watched this movie. We discussed it at work the other day and she (being an engineer) pointed out all of the inaccuracies that make the movie hard to take; the objects being in the same orbit planes near each other, use of Hubble instead of some other made-up satellite, the silliness of the Kessler Effect taking out all satellites in a matter of minutes, including LEO and GEO regimes, and on and on. Even the nonsense with Clooney dancing around the HST firing his jets and running at the mouth for no apparent purpose and with disregard for the safety of the equipment.
She was a lot harsher on the movie than I was, but she still liked it for the hardware realism, the visuals, the pacing, and the well-done acting of Bullock.
But she had a point: why go to all that trouble and spend so much money to get so much right and then just not care about getting the rest of it right?
That's what always bugs me about these kind of movies, too. In the end, they all rely on the ignorance of the audience, disappointing those of us who know better.