it's entertaining, but very badly written. if you can suspend your disbelief for 2 hours you may enjoy it, but other than directing it has nothing worth praising.
no, really, it's ****
to elaborate. the characters don't feel alive, they don't act or talk like real people do. the story itself is plain stupid. two main characters that drive the whole movie are portrayed relatively well, but neither Clooney nor Bullock looked like they were the only actors to do their roles justice, if you know what I mean. they do have good chemistry, can't take that away.
overall, a generic soft sci-fi disaster movie with boring camera work and special effects. Cuaron deserves all the praise he got for directing two people against a blue screen in a two-hour snore fest and getting such a successful movie out of it.
meaning, if you're really into movies, it's worth watching for insight into how to direct **** scripts the right way.