But the Apple TV 4 is archaic. Is there any other major box that hasn't already been playing 4K content for some time now? The last few years Apple has been selling yesterdays technology at tomorrows prices. I applaud them for being able to get away with that but I doubt that will last if they don't get back on track soon.
I always purchase movies, never rent. Today that is about 90% digital vs 10% disc. You don't need to side load anything on Roku. Between apps and private apps nothing compares. If somebody ever makes something better I'd be happy to switch, I have no brand loyalty. Of course if kodi or jail breaking/ side loading is your thing there are hundreds of cheap android boxes for those people.
I thought I mentioned I use FireTV 4K + Kodi (I'm testing Embry with it right now as well). I haven't bought an AppleTV since Gen2. I keep it around connected to a separate DAC on my analog preamp based system just to be sure I don't get skips (Kodi has some odd music issues they refuse to address; it's a reason I'm testing Embry right now). I did read an Embry App is available for Roku so you might have a way to play your own media library, after all with it.