I have been to China twice for 14 days each time. I have been to Beijing, and Shanghai. I personally preferred Shanghai. I have also been to the old capitol Nanjing, a lot of history. Shanghai felt better than any other. Find an ExPAt online and ask some questions.
shanghai i have been there it is a very modern cosmopolitan city and foriegner friendly
Beijing....because it's the capital :D
Dunno, never been to China