I just checked out the MX4, but I don't like the design of the phone, to be honest.
The Mi4 is just really beautiful..
Another noob question: I heard that can be a real challenge to get genuine earphones
from Xiaomi. So do I need to worry about counterfeit cell phones also, or is it safe
to assume that if it looks like an Mi4 on the first sight it also is an Mi4?
Yes, there are some counterfeit phones, fake Mi4 included.
For instance
http://android.tgbus.com/xiaomi/wanji/506003.shtml (in Chinese)
What the webpage tells in general is that the fake ones are in many ways much inferior than the original one, while having almost identical appearence.
The safest way to get genuine Mi4 is through Official Website mi.com
Xiaomi's flagship store at tmall.com(Alibaba):
http://xiaomi.tmall.com/ is also considered to be trustable.