Gosh, my wife has a hard enough time working the TV with a remote.
I may have mentioned this, but if you own a Windows or Android tablet, the XBMC/Plex remote apps available for them are super, super sexy. My mom can't work a TV either, but does pretty well once she's in Plex.
I still think the FireTV is pretty nice. The Chromecast is way, way better than it was at launch, though it's clearly targeted at younger users since it has a tablet/smartphone/PC as an absolute requirement to using it. Roku is just a one way ticket to a laggy UI, but it's still piles better than all the crappy functions and remotes on every Smart TV I've messed with.
Porkchop Sammiches said:
The dedicated PC will win on full functionality at the expense of price, complexity, size, and noise.
My NUC was built out of spare parts I just had sitting around other than the barebones NUC itself. It doesn't make any more noise than any other STB and it's only a tiny bit bigger than a Roku 2. The Start Screen actually makes a great UI since it amounts to a 10' UI for 10' UI selections of Plex or Netflix or Youtube or XBMC. If you have RAM and an 802.11 card sitting around, you could probably get one of the Celeron models running for $200, which doesn't strike me as outrageous given the benefits over the STBs.
I do wish there was a better experience for local media among the ModernUI ("metro") apps; all the stuff in the app store is really just front-ends for Spotify or Pandora or Last.FM or something and while I'm OK with the XBMC presentation, I suspect that it could be improved.
I suspect that even the entry-level 4k displays will look really damned good for most applications. I wish I hadn't bought a new TV in the last 12 months.