https://youtu.be/uzjC64FKzWo
The above is a good summary why Mi Box S is often recommended as the streaming device to go.
1) It is a streaming device which makes your TV smart or smarter than it is now. This is true for TVs like those Samsung Frozen OS based smart TV, LG Webos based smart TV and even Xiaomi TV running Patchwall Android based OS.
2) It runs official Google Certified Android TV OS which is easy to use.
3) Very good streaming support due to running Certified Android TV OS, Netflix 4K and YouTube 4K are supported.
4) Good voice remote with Google Assistant
5) Chromecast 4k function built-in. This is one of the best feature of Mi Box S. You can use apps like Netflix, YouTube, Starhub Go, SingTel TV Go, Singtel Cast, Toggle, HBO Go, Viu Premium, etc, on the phone (iOS or Android) and then cast to your TV with this function. Basically this covers most of the popular Streaming services here in Singapore. Take note you can still use your phone for other things after the shows started on the TV. You can run Netflix, YouTube, SingTel TV Go and Singapore Cast on Mi Box S itself as well.
In terms of cost, typical cost in Lazada/Qoo10/Shopee is around S$70-90, depending on offer and coupon. Take note Chromecast Ultra (4k support) itself cost more than S$100. Even the cheaper Chromecast (1080p) costs more than S$50.
The main disadvantages of Mi Box S are the following.
1) The author mentions relatively weak CPU and occasionally lag or skip frame if you set the interface resolution as 4k. Still it is actually very good for streaming and even casual gaming due to good software optimization.
2) Relatively limited interface, only one USB 2.0 port and no Ethernet interface. Still take note the Dual Band AC WiFi works well.
3) Relatively small 8GB storage but you can add a fast USB Flash Drive to expand the storage
Nvidia Shield TV (usually S$200++) have all the advantages of Mi Box S and none of the disadvantages of Mi Box S.