I have not moved the asus router as it is my office, next to my switches, firewall and servers and it keeps it simple. and the house is not a large house, was originally a summer cottage, then added on, then added on. The visio's are really actually good at working with plex, but I'm not running 4k, but the ease of use. of course the size of the files I run through plex vary, 1GB to 50GB, (but figure the average is around 4 to 9 GB) and I am happy with how it works, go on vacation, just run it through the roku etc, ease of use is excellent.
also, the kids can use it, I have some coworkers that are connected to it, my nephew at college, etc and it works easily.
I think of plex as an easy way to have your stuff organized and accessible without issues. I can connect using pretty much any device, from xbox to cell phone.. amazon tablet, etc. And it's quick, quality wise, it is either 1080p, or close enough that I can't tell the difference, and am happy.
for music I just use windows. It's simple and it works. I have a netbook on the porch that connects to my media, a windows tablet it the Living room that does the same, and each person can create their own playlist, or stream from you tube, etc. and anyone can access it and I don't have to worry about them deleting, or renaming, or messing up other playlists...