[Xiaomi Mi Mix 2S Guides, News, & Discussion] jhs39:
I was on Global Developer Build 8.8.4 and decided to try the China Developer Build because of all the raves it received in this thread. In case anybody else is thinking about doing the same I want to write about my experience. I was on China Developer Rom 8.8.13.

The China Developer ROM wasn't faster or smoother than the Global Developer ROM. Maybe some people used AnTuTu scores to convince themselves that the China build is faster but I noticed no difference. The notification shade also doesn't look better in the Chinese ROM. As far as I could tell it looked exactly the same as in Global.

Google Play Services are already included so you can install the Play Store to download your apps but there are limits to this approach. I couldn't choose Google as my default search engine. That wasn't exactly a surprise since the search engine is specifically what caused the rift between Google and the Chinese government but I use Nova Launcher and the Google search bar on the Nova homepage didn't open Google Search even though I had Google installed. Instead, it opened the system search engine and all 4 choices (including Bing) operated in Chinese even though I chose US English as my default language and the United States as my default region. But the Google feed option on Nova did work fine.

There is no way to set Google as the default voice assistant. There is no option in the MIUI settings for anything other than the Xiaomi Assistant (which only works in Chinese) and when I tried to enable Google Voice Assistant from within the Google App I got a message saying that settings had closed. Using Ok Google commands from within the Google app also returned error messages saying that the feature wasn't available in my country. I only tried a couple of searches involving the Google Assistant so it's possible that some queries work.

The MIUI Theme App is in Chinese, more than half of the available themes are paid not free and after several hours of browsing, I only found a few themes that I recognized from the English language version of the app.

The Chinese ROM comes with a number of China only apps although most of those could be uninstalled. Some Xiaomi System Apps that can't even be disabled on the Global ROM can be completely uninstalled on the China ROM.

The built-in root option on the Chinese ROM didn't work. Some options in the Developer Menu also didn't work. When I tried to enable the install apps via USB option I got an error message saying I didn't have permission. I also got that error message with another toggle but I don't remember which.

The Google Smart Locks options seem to work the same way on Chinese and Global--the on body detection can be enabled at setup and the Bluetooth device unlock can be enabled via the popup notification after connecting a Bluetooth device. I was surprised that Google Smart Lock options were included in the Chinese ROM at all.

The stock English language keyboard still had some Chinese characters on it.

I went back to the Global Developer ROM after a day and a half. I intended to use the Chinese ROM longer to give it more of a chance but a day and a half was honestly all I could stand.