Vantaggi
Get global exposure, coordinate with cross culture folks, ability to work on a product which impacts millions (e.g. MIUI, TV etc). I joined a new team - MIUI which we are starting from scratch in India. MIUI is the Android-based OS which is installed on all xiaomi phones. So if one is hungry for knowledge there is a lot of learning wrt Android, platform, kernel till hardware layer. After joining I realized there is soo much scope of interesting things to do in India and we have not yet started. This is on the comparison of tech infra which we already built in China. You can learn a lot when working with Chinese as they are very similar to Indians and are intelligent. So it is a fun+learning experience.
Svantaggi
Nothing xiaomi-specific. The kind of user problems which we try to solve are very difficult, one bug can impact thousands/millions of users so we have to be extra careful. But I believe if you want to solve easy problems, join TCS, Infy, IBM, Accenture not Xiaomi.