Today I installed HarmonyOS on my China model Mate30 Pro.
Here are my first impressions:
I love the new design, much better than the EMUI of old. The animations can be a bit sluggish though.
It runs great.
It is more a new skin on Android, not a new OS. Something Huawei seems keen not to mention.
It's very complicated to install for some reason, I had to download a random APK and then go through many Chinese language menus to finally install the profile.
The new system font is really great.
Overall, it's more like an overhaul of EMUI than a new OS, all Android apps (including Play Services) still work.