Repost, from my page 94 posts, with some updates.
So Mi Box S is the top choice for sub-S$100. And Nvidia Shield TV is the way to go if you want the best performance and best gaming experiences for an Android TV Box (no point to compare with latest XBox, PlayStation or Switch or PC Gaming though).
Then why I still recommend other TV boxes sometimes?
1) If you need some special requirements, like Video Recording, then you may want to look at Zidoo with HDMI input.
If you really want a hybrid box with DVB-T2 Tuner built-in, then you may want to look at Mecool Kiii Pro and Magicsee C400. If you want best blue-ray rip file playing device, you may need to look at Zidoo X9S/Z9S/X10/etc, Egreat, Himedia Q10 Pro, with HDD interface and BD menu support.
2) If you are not relying on streaming service like Netflix, or apps like Toggle, Starhub Go and Viu Premium which work best with Chromecast, or TVB Anywhere+, or SingTel Cast, then you can consider boxes with better hardware specifications (CPU, RAM, Storage, USB ports, Ethernet ports) than Mi Box S.
For example, you are using Kodi and other streaming apps (for examples various Chinese streaming apps for VOD and Live TV), then boxes like those with the S905X2 CPU (eg, Tanix TX5 Max and Beelink GT1 Mini) or S912 CPU (older Minix NEO U9-H is a popular example).
3) If you really have budget constraint to below S$50, then you can consider low cost S905W based box like Tanix TX3 Mini 2GB/16GB and Tanix TX3 Max, around S$40-50. The WiFi performance is not good though.
Tanix TX6 is a pretty decent low cost device which has much higher performance than Tanix TX3 Max and TX3 Mini, the only problem is that it has a bit of thermal problem which can be easily sorted out with a USB cooling fan blowing wind from the side (no cooling ventilation holes from the bottom unfortunately). If you are willing to use a fan, it can be recommended as well.