Hope this is not just another price war type company. There is little innovation could be done by this company. Screen, Chipsets, CPU are all done by others. Lets see, I am not that positive, hope I am wrong.
As well as shortening the supply chain, and make things "just-in-time" (maybe it's just artificially controlled...) Xiaomi demonstrated the importance of branding and marketing.
I think..... apart from it being cheaper, it had generated the hype for people to follow.