I switched from Roku to Xbox for Plex because of how Roku has degraded, and not only did I get the primary benefit of being off Roku, but I found the Xbox Plex app has not been updated to the terrible new redesign so it was a double win.
In ~2015 got an Xbox one, as a media center it was an awesome experience:
Kinect voice control to play/pause and other things way before Google home/Amazon echo ecosystem were mature.
Free OTA channels via TV tuner and well designed OneGuide (with ability to pause and rewind).
And of course all the Netflix and other apps, Plex server etc.
But strategically it seems Microsoft decided they wanted to look more like Playstation, focused on gaming (at that time paid Xbox live subscription vs free Playstation)
And as gaws points out, they seem to recently announce to double down on the gaming stuff.
So when they discontinued OneGuide. I picked Roku since they seem to be focused on the media experience primarily... but unsure how I feel about this acquisition news.