I've read a couple of articles this week which say that his trip has been unsuccessful because he has not really confronted the big "Asia issues" which confront the US (trade, debt, and - with respect to China - human rights). In this morning's New York Times, Helene Cooper and Martin Fackler summarize the trip's shortcomings:
Even his two sightseeing trips [to the Forbidden City and the Great Wall] ... were prominent, well-publicized examples of what Mr. Obama did not do in China. He steered clear of public meetings with Chinese liberals, free press advocates and even average Chinese, with his aides citing scheduling conflicts. Mr. Obama did, though, give an interview on Wednesday morning to Southern Weekly, one of China’s most popular newspapers, sometimes known for poking the authorities by breaking news on delicate subjects.Still, for an American president who has tried to make openness a hallmark of his public persona, it was a departure, made more stark since Chinese authorities largely hijacked Mr. Obama’s one other attempt at a give and take with Chinese students, a town hall meeting in Shanghai, by stuffing the auditorium with young Communist Party aspirants.
Here's a picture of Obama at the Great Wall - it's by Stephen Crowley of The New York Times (like the other pictures I've seen of his walk along the Wall, the overall mood is rather gloomy):