I've been living in China for the last few years and have had the pleasure of working at the last few international skating events here, including events in Harbin, Beijing and Shanghai. From my experience, Chinese crowds tend to be extremely patriotic and reserve their excitement for homegrown skaters and some of the really big names from abroad. This increases depending on the city - Shanghai being relatively cosmopolitan and having a large international population is more western in their behaviour. Beijing is a little less lively and Harbin can be almost icy (at the Winter University Games, no Chinese female skaters made the top group and a large chunk of the audience left before this group started despite it containing the likes of Kiira Korpi).
Having said this, the crowds are gradually becoming a little more open... I think... maybe?
This is just my perception and others are welcome to disagree, but even a Chinese skater I was talking to recently said that crowds in Japan and other countries are much more lively and generally welcoming of international competitors.
Regarding Shanghai vs Beijing, the 2011 & 2012 Cups of China were in Shanghai, this year back to Beijing, but next year it will be back to Shanghai again as a trial run for the World Championships in 2015 which will be in Shanghai.
Oh people are so nice. I'm going to give the honest answer: Chinese people, excluding the diehard fans, which is in the number of hundreds, don't know **** about figure skating. The public doesn't, or doesn't know how to appreciate things they don't understand, and doing certain courtesy things like applauding just to be polite is just not a thing in China. People here react to things more in a natural order. When a skater falls all over the place some might feel no applaud is deserved.
That being said, the two CoCs I attended in Shanghai the past years looked better than this one. It was almost a full house after dance in free skate last year and the arena is brand new and huge. From where I saw, in the VIP seats closer to the rink were mostly Japanese people, serious, traveling fans. A lot of families got free tickets from work it looked like. You could also buy tickets at the door through those illegal vendors for dirt cheap. I paid about 40 US dollars for everything and I heard today you could buy an all-day free skate ticket for 2 US dollars in Beijing...
For those who want to come to 2015 Worlds, the Shanghai arena itself is truly gorgeous at night, nothing like it, but don't count on the seats getting anywhere close to the ice. It's completely frustrating.
I would not call the audience subdued, the good performances got the deserved applause.