Not bad, surprisingly. The Farewell offers a window through which westerners could see and appreciate common Chinese beliefs and values manifested naturally in people's daily life and interactions. It does a good job to present modern China and its ecosystem on a micro-level, i.e. family, without sugarcoating or demonising it. I understand why some Chinese audience may argue that the view of culture differences (expressed explicitly through conversations) is superficial, but I think this superficiality actually renders it particularly true, because that very view is held by actual people - it is not imagined, and it is not profound for a purpose.
Authentic, almost ethnography-like, but I'm not sure if it's such a good thing in a narrative film. While this is laudable for Asian representation in Hollywood, the next step is for Asian Americans to play roles beyond ethnic stories.