I have a couple of QNAP NAS boxes running twonky media server. Stream to all my Apple TV 4's via either an app called infuse or VLC. I also have a Beyonwiz T4 that has a dlna server built in so I can watch shows off my PVR with VLC.
I'll often watch a show in one room while my wife watches something in another and never have any issues. In fact it's pretty stable. Because we rent I had to run Ethernet over power to the lounge room. This worried me, but surprisingly it hasn't missed a beat.
My iTunes library (tv, movies and music) is run off a pegasus promise box plugged into my Mac Pro. Where possible I run Ethernet, however the Beyonwiz and all ATV4s are wireless.
QNAP and twonky are easy to set up and run. ATV4s are the way to go. VLC streaming is fantastic. I ditched all my ATV3's and upgraded when Apple were selling ATV4's on the refurb store.
In terms of gaming devices, we have an Xbox one, Xbox 360, 2 x ps4s and a PS3. Plus all our TVs are on wireless and no streaming issues at all with games and videos etc. but for video we just use ATV - so much easier and faster more robust.