How about a Shield pro thingie? Upscales to 4k well, atmost too. Or so my friend says.
I thought about getting a new one. If you need/want a media hub sorta deal they seem to get good reviews. And bonus you can stream from PC to TV pretty well, too.
I had the hand-held controller version of their Shield and it was awesome for streaming games to the TV (especially being portable, used to play GW2 on it while visiting inlaws out of town). When the screen broke completely on its own and having nothing to do with the angry pressure of my thumbs, I still had it plugged in and was using it as a media hub to good effect for a while when my old plasma TV apps started not being supported. So, I can vouche for their older version and the concept, at least, as it was cool little device that worked well.
I didn't get the latest generation because it seemed redundant as we have app-boxes x2 for every TV it seems between roku and smart TVs and consoles and BluRay players, and I personally just went lazymode x-box gamepass for gaming with a controller, so it works fine for our main media hub. Rarely I'll still sit at my computer like a punk when there isn't good controller support (or if I want to use my racing wheel). And the rat-race of trying to chase the latest tech for +1 better sound or picture isn't worth it anymore so netflix on my xbox or roku tv is whatever enough for us at this point.
Nvidia Shield seems redundant if you get consoles for gaming or are a hard-disk aficionado so have a decent bluray player as you'll have all the same apps and functionality except for streaming games to PC.
Maybe if you travel a lot and want something portable that isn't a big console or dealing with a phone? That was one of the nicest things about the Shield portable I had, could access apps and load a sim card with movies, plug it in with just a HD connection, and even play PC games if you set it up right and internet wasn't too spotty in the hotel. Then again, last time on a more extended trip I just took the xbox like a nerd and it wasn't too bad either, so, shrug, almost too many ways to do the same things these days.