I second the Shield as the best android tv box, I've had a wide selection of android tv boxes, while the off shore ones have come way up in quality and stability they still can't touch true android TV.
Currently I have a Nexus Player and Nvidia Shield. Very happy with both. Shield is great for gaming. If you really only want for Netflix, Youtube, Google Music etc. try out a Chromecast. I run a couple of those too,
Chromecast main draw back is non-supported apps. Prime Video off a PC works, but off a phone or tablet, not so much.
Been trying to get a hold of a Mi Box too.
Sony 75" X940D, 7.1 Klipsch, Onkyo TX-NR656, Xbox One/360, Nvidia Shield Alienware Alpha, Arris Gateway, 42" Samsung