The Xbox One S is the best console ever made for one, pure, number-crunching reason: it's the only gaming box currently available that can pump out games High Dynamic Range, making the most of your 4K TV.
"But I prefer PlayStation's exclusive games."
Then buy a PlayStation 4.
"But I love retro games..."
Then wait for Nintendo's little NES to arrive in November.
"But I don't own a 4K TV..."
Ah. Right. In which case, here's how things stack up:
Already own an Xbox One but don't own a 4K TV? Don't bother getting an Xbox One S unless you really, really want your console in a nice shade of white - you won't be able to experience the full benefits of the console until you get a screen that warrants the upgrade.
Don't own an Xbox One but want a new console? The Xbox One S is an equal to the PlayStation 4 - you should base your decision on which exclusive games you prefer and which interface you feel most comfortable with. If you've been using an Xbox 360 and still not splashed out on any of the latest consoles, the One S is probably the most natural fit for your gaming habits.
Got a 4K TV? Then this is the box for you.