It is not fake. It is just intended for Chinese market. System has some differences. There is no OTA update, it will be harder to find how to root the device, sometimes there are some hieroglyphs next to the English translation etc. I've the feeling battery is draining a bit faster but I have nothing to compare to, maybe it's just paranoia. Hardware is the same. The device is working fast and I haven't experienced other problems (bought it two weeks ago).
It's half the price after all.
I've already found one bug:
can't change alarm tone, ringtone.. and all other notification sounds in the system settings. But apps like Zedge can. About the alarm sound you will need different alarmclock app. Maybe there is a solution. If you find it, please share.