It's not just China. It's a general problem with any high-latency link (for example satellite or mobile broadband.) These redirects easily added 2-3 seconds to the latency of retrieving a page when I was working over satellites at a remote retreat center. And that was as you say on a good day. Hanging connections were very common, I often had to do a hard refresh on various Google Apps to get them to stop the spinning wheel of death.