Mi A3 is Android One. Which means that it will receive regular updates and also 2 major Android updates that is in total 3 Android versions including the original one, compared to just 2 versions for Redmi phones. I prefer stock Android than MIUI. You will get more battery life, better multi tasking due to more free RAM, longer support, better security and less bugs. If you don't want to experience irregular updates and delays like in Redmi S2, then Mi A3 is the best in terms of the price and support.