My favorite set top box company continues to evolve with the Roku Premier.
The new line of Roku units are faster, higher resolution versions of the old. The UI is the same, the same apps are available, everything is just a lot faster. I replaced a Roku 3 with this Premier unit.
The Premier is also 4k ready at 60 fps, although I have nothing that'll display that currently.
Roku Premiere Streaming Media Player via Amazon