Device? Depends where I am and what I'm doing I suppose. A Mac mini is the cat's meow IMHO. It is my main device for watching "TV". It also makes it trivial to stream anything any way I want to my other devices.
Other devices would be something iOS. iPad's, touches, and iPhone's depending on location / use there. VLC usually going back to my library directly (or live TV).
I've used Plex for management, but really don't anymore. Too much database corruption problems with it. Easy to do though as it's just another avenue to scan libraries.
Connected to the Mac via bluetooth I primarily use a numeric keypad with most of the keys re-programmed / re-purposed -- depending on the APP [BetterTouchTool].
One key is space (play / pause pretty much across the board). 0-9 tunes the TV for EyeTV, whereas I decided "6" changes the aspect ratio for VLC.
Across the top where function keys -- now APP keys:
EyeTV Netflix Sling VLC iTunes
Other keys programmed differently, but universal for function, ie: one key is "G" (guide), another now says "F/S" (FullScreen on/off), etc. +/- channel up/down in EyeTV, but will play next/previous song for iTunes. No function in Sling. So on and so forth .... BetterTouchTool.
That's the primary remote -- the secondary is a old iPhone pretty much running BetterTouchTool -- which allows you create custom menus on the display along with acting as primarily a mouse pad...
Running a full blown Mac gives you WAY more options than just a AppleTV (tried it upstairs, meh), Roku, Chromecast, etc... The Mac wins in this case -- hands down IMHO. It helps that ssh / bash / unix is the under-pinning for remote access whether locally in the same room or from work... Of course my desktop there and at home are other Mac's. :)