The big ones for me are built-in Google Cast, actual customer and software support, and not having to wonder if there's any malware installed. It doesn't hurt that the Tegra X1 is a fucking beast of an SoC. The chip is over 2 years old yet still outperforms any other box on the market.

I'll note too that my primary interest is in gaming and gaming selection in addition to streaming.

Then the Shield TV should be the only device you even consider. Otherwise just hook up your gaming rig to the TV or buy a Steam Link.

Android boxes are typically barely supported and have garbage hardware. They should have full access to the play store however but some apps wont work properly. Android TV is officially supported by the apps that are in the TV store such as Netflix. Shield has access to more apps than other Android TV devices like Amazon and Vudu. I couldnt see a cheap android box handling games as well as Shield does.

DRM support and continued updates. Look at the Nexus player that just got Android 8. It launched on 5.1.1 in like 2014.

"Android Box" means that the box has the tablet version of Android.

"Android TV" means that the box has the official Android TV OS, which allows for more TV specific apps, and you can get Netflix in HD and surround sound. Something that the tablet version doesn't have.

You said gaming is important get the shield nothing games like it other than the other shield devices

Android boxes usually perform really shitty and you must be really lucky to get one that gets OS updates (which you will have to apply manually)

FYI any app you can install on a regular box you can also install on a Android TV, just not directly from the app store. You can also get a mouse remote from Minix or whatever to navigate sideloaded apps.

I used to work for a company that made just "Android boxes", and they honestly were better than most and fairly well supported. A good company based in the EU and a lot of good people. But...

1. DRM support for Netflix and such. My former place of work actually had proper DRM support on their product, but even then Netflix still screwed them and locked the app down even more so. They're a small duck in a big pond, so it's not like Netflix is going to bend over backwards to help them fix the problem, either.

2. Support. The company I used to work for had several full time Android devs working on firmware, and there's still a ton of bugs and issues with the devices. You really need to be a big company with an ear with Google to nail down some of the finer points, like HDR, various audio passthrough options, etc (many of these things Google is still nailing down themselves). Even just stuff like game controllers could easily be a nightmare. One controller, fine. Two controllers, and sometimes the thing freaks out, etc.

3. Price. You can't beat the MiBox for a good box that also supports proper DRM frameworks, and you can't beat the Nvidia Shield for raw power in any ARM-powered set top box, period.

4. Chromecast/Googlecast support. This is something others cannot have without Google's direct approval.

In the end, my home runs actual Android TV boxes for media centers/OTT/games. I have a Nexus Player, Shield TV, and MiBox, and I'm looking to buy another MiBox. There's just no point in messing around with the cheap boxes unless you're looking to tinker/hack or something. They do have a place, and you can actually do a lot of neat things that don't need what I've described above, but for entertainment I don't see the point in getting anything less than full blown Android TV.