Lol I agree,I'll buy one second hand some day probably to see what the fuss was about. Any decent box with Widevine DRM Level 1 and some tweaks can get you true 4k UI and playback,uhd Netflix and 1080p DStv easily though
Xbmcfan is mostly correct,most 4k boxes running Atv including the Shield had a upscaled UI being a fault with the Android TV UI. Shield fixed it a while ago but other boxes including the Mibox cannot do true 4k,this effects playback as well.
Most people won't notice it though.