We haven't had any reports of problems, but we haven't tested in China ourselves so we can't give a firm answer. While we’re not aware of any issues using Pusher Channels in China, we can’t really make any guarantees of service due to China's networking restrictions.
We don't host Pusher Channels in China, but we have AWS regions in Asia: Mumbai, Singapore and Tokyo. Please refer to our documentation for more information about regions:https://pusher.com/docs/channels/miscellaneous/clusters#what-clusters-exist-