Here in India at least, these Chinese brands along with Lenovo have pretty much become household names in respect to mobile phones.
And they do make good, solid, innovative products at half the cost of their Korean counterparts. From an Indian perspective, It is no surprise that Samsung is bleeding to these (at least in the low and mid segments).
What is truly amazing to me is the pace with which the reputation of these mobile companies were built. It took years and even decades for the Koreans (Samsung and LG in electronics, and Hyundai in cars) to be taken in the same respect as the Japanese. The trust and reputation of the chinese brands (in the mobile space at least) were built almost overnight (and sooner in cases like OnePlus). There is certainly a Tom Sawyer effect in play with use of marketing tactics such as invite-only and flash sales.