Do you not have to alt-tab when you want to pause a video on a secondary monitor when you are in full-screen mode? How do you get focus on the video player?

As far as performance goes, I don't think there is much difference. And if they are only going to add full screen or borderless, borderless is the one most people are going to want.

I personally prefer borderless as tabbing in/out of the game is instant and leaves the view up, which is great if you need to take notes on something in the game.

I have a fightstick in my lap and a keyboard on my table. If I focus the video the controller still works (on the fullscreen game on a seperate monitor), but I can also tap space, arrow keys, m for mute, c for captions etc. without the need to alt tab or use the mouse.