Amazon Fire TV Cube
The Fire TV Cube is currently the most powerful media streaming device by Amazon.
It can play upto 4K 60fps video with Dolby Vision and Dolby Atmos support. It also supports HDR10+.
The specs include a hexa-core processor, 2GB of RAM, and 16GB of internal storage.
Software & UI
There's built-in Alexa support but also some ads in the UI. The reccomendation algorithms can be confusing for some.
It has a dedicated button to invoke Alexa along with specific Hotkeys for Prime Video, Netflix, and Amazon Music.
There's a micro-USB port for the ethernet adapter, the IR port, an HDMI port, and the power adapter port. It uses Bluetooth 5.0.