I have two and watch YouTube and my kids KidsYoutube every day without hiccups. DSTV now and others also works just dandy.
It currently does not do official Netflix though as they have not approved the box just yet. But there are ways around that.
The Lit Box will also give you an Ethernet connection and Android 7 - both which are not available on the MiBox.
Source : https://mybroadband.co.za/vb/showthread.php/938699-Mediabox-MBX4K-or-Xiaomi-Mi-Box-4K