From the horse’s mouth
The Apple TV has ruled the roost as an add-on set-top box that ties in tightly with their MacOS and iOS platforms. Here, this set-top box has access to an app store with the native-client apps for the main online video content services amongst other things. This is in addition to being an audio-video AirPlay destination for streaming content from your iOS device, Mac regular computer or iTunes software.
You have to have your Apple TV bound to your Apple ID account (of which many such accounts can be bound to the same device) but you can control it using its remote control. This can be either the Siri Remote which is a Bluetooth voice remote with trackpad operation or the classic Apple TV remote which is a simpler infrared D-pad remote. You also had the ability to install native client apps for the popular video-on-demand services, while it existed as a front-end for Apple’s iTunes transaction-based video-on-demand service.
Newer iterations can be bought that can offer 4K UHDTV video and all the newer tvOS-based Apple TV devices use HDMI-CEC control, allowing you to press any button on the Apple TV remote to cause your TV to come on and switch over to the input the Apple TV is connected to.
But those of us who use the Android platform weren’t sure of any add-on set-top device that works properly with our phones or tablets. There are some TVs that run Android TV and some set-top boxes do work this platform but you need to be sure they aren’t running the mobile Android operating system rather than Android TV. As well, some of these Android TV set-tops run an “operator-tier” variant of that platform which may limit access to the Google Play app store for Android TV apps.
Or you would simply use a Google Chromecast device or a smart TV or set-top device that fully supports the Chromecast (Google Cast) streaming protocol and stream video content from your Android device to your TV using that device. This would have you keeping you Android device on while you were viewing the content and being aware of its battery status.
Now Google have offered their latest Chromecast device which is really a Google TV / Android TV set-top box rather than just a Chromecast-protocol audio-video endpoint, dependent on your smartphone. This device, called the Chromecast with Google TV, has its own remote control which is a Bluetooth / infra-red remote voice remote, along with an Android TV operating environment and Google Play app store.
This device also provides a unified content-search experience so you can search for a title and it will show you if it exists in any video services you subscribe to as well as offering you the ability to view it through Google’s Play Store’s transaction-driven video-on-demand service. The voice remote also allows you to search for content using your voice and Google Assistant.
The Google Chromecast with Google TV will require you to bind it to your Google account. But I am not sure whether this device offers multiple-account support to cater for multiple-adult households.
It has a USB-C connection that is primarily used for power-supply purposes but Google is wanting to see it used as a data connection for supplementary peripherals. The use they initially have in mind is an Ethernet adaptor similar to an Ethernet-equipped USB-C hub that implements USB Power Delivery Charge-through (pass-through) support. But it could be a chance for Google to supply and support a companion Webcam as a way to purpose this device as a group videophone.
At least for Android users, Google has done the right thing towards having an add-on set-top device that is a known quantity which provides smart TV functionality.