Why not cost efficient? I was planning on getting a Chromecast Ultra, but then I realized I could get the Xiaomi Android TV for the same price with loads more functionality. The only think the Chromecast Ultra has over the Mi Box that I can see is a little more portability, which doesn't seem like that big of a deal for something that usually stays plugged into my TV.
If anyone's wondering the guy modified the build.prop of his device and a few other files into spoofing it as a Razor Forge. AFAIK all the Android TV-ness of this interface isn't some mimicked UI, it's pretty much Forge. Because it's spoofing a forge you'll still have most of the problems that came with it plus a whole bunch from the Chinese hardware.
The extra apps in the "Play Store" store are interesting though, I wonder how much can be acheived by running AndroidTV on unofficial devices.
The Wetek Play 2 is a standard Android box. A user created an Android TV boot for it in his spare time and it works pretty well. Got all the codec's working with it. It's not official Android TV but it's basically the same thing. Not sure if it can do 4k on Netflix or Youtube but it can do 1080p for sure. Only problem is the Play 2 is $120 new and you can get the Mi Box for $50 less which can do official Android TV. The Play 2 does have a DVB/ATSC port in the back for OTA broadcasts so you don't need to change inputs to your TV or buy a HDHomeRun/Tablo.