Performance of mi 4a router wifi range

I am looking for a router . I have seen the mi 4a model of xiaom gigabit edn. Can you tell me how it's performance. Im asking just because i have seen many unsatisfying reviews about the wifi range. Hence as I don't have the device in my hand now . i want to buy it and then for sure i will insyall openwrt here . as its on a discount can be bought at $16 or so.
Also does it have mu-mimo(

Here are the reviews