Not quite what I expected. It was more of a character study, less of a romance. Carey Mulligan, as everyone has said, was perfectly cast but other performances stood out for me. It was the first time I was really impressed with the acting of Rosamund Pike, as opposed to just being impressed with how pretty she is. Her and Dominic Cooper not only look amazing together, playing a slightly amoral, more-than-slightly shallow couple. With very little, they both register a lot: boredom, self-satisfaction, sexuality, even sadness. Alfred Molina - an actor with seemingly unlimited range - was perfect as the class-anxious father, and I loved Olivia Williams, as Ms. Suggs, a character straight from a Barbara Pym novel.
All this added up to a very good film, although the tagged-on, tied-up ending was a disappointment.