I've been using the first build for an afternoon now, and everything appears to work without much problems. GPS is fast, Wi-fi doesn't disconnect, and battery life seems to be the same as with CM13 ROMs (I expect around ~6h of screen on time with my use).
The only negative side I can mention is that I can't seem to change the SIM card color (I'm used to my private card being red and the business one being blue, right now they're all the default shade of blue), but it's really no biggie and I'm sure it'll be fixed eventually. Dual-SIM itself also works without any problems so far.
Congrats on a great build
P.S. Nothing to do with the ROM: AndropaX, could you possibly look at the touchscreen issue thread:
http://forum.xda-developers.com/mi-4c/help/touchscreen-issue-exists-t3274446/page6
The latest MIUI dev builds seem to have fixed the edge multitouch problem the Mi4c has and not a single custom ROM has integrated the fix as of yet. It's one of the few more serious problems remaining. I don't know how difficult the fix is to implement, though, but it'd be great if someone who knows what they're doing looked at this. I've tried flashing the MIUS firmware_update on a custom CM ROM and had no luck.