I own a Sony KD 49X8005C with Android TV, but the interface is quite laggy and the connectivity over WiFi a pain in the arse. The plex app often loses connection mid-play and most of the time it only establish either after a reboot or after like 2-3 minutes. Unfortunately, it's not possible for me to use an ethernet cable.
That said I am now considering upgrading to either a Mi Box S or Nvidia Shield TV for better and stable connectivity. I am not seeking for performance, because I just use apps like Plex, Netflix, Spotify, and IPTV.
Will the Mi Box S be enough? How's the WiFi at the Mi Box? Compared to the built-in Android system from my Sony it must be easily faster and more stable. Further, I am still stuck at Android 7.
Shield. The Mi Box is OK, but if you want an upgrade, get an upgrade. You won't regret it.