It entirely depends on what you play.
It's not possible with absolutely max-ultra-8xAA-modded-customtextures-shineyballs settings in the top few most demanding games, but you drop the settings from ultra down to high or very high then you've got a very good experience at 4k and the 99% of the rest of any decent sized gaming library will run maxed out.
I love the really high fidelity that some titles can crank out, the Crysis-like games which are so pretty it makes your eyes bleed, but I probably put in close to 1000 hours of gaming a year and the latest Crysis-like titles probably account for maybe a total of 50h of that.
Some people literally only play CS and TF2, or MOBAs which all easily run maxed out. It's easy to lose track of reality when you're looking at benchmarks of the most demanding games in the highest settings, these are used to show off the power of the cards, but for most people that's no representative of their actual gaming habits.
Those aren't even maxed settings. It's like FXAA or 2x MSAA.. 2x Fury X isn't enough to max 4K with 4x MSAA.
Neither would 2x Titan X.
4K is about trade-offs, higher resolution vs maxing IQ in games.
Now compare how games tend to look on High/Ultra vs All Ultra. Much difference? Hardly any.
Lot's of truth here on both accounts.
Not only do we not always play these most demanding games, but as IQ improves, we start to see diminishing returns on how much better things look at higher settings. The same thing can be said about resolutions. Resolutions also effect IQ.
I'm not sure why in game settings have to be maxed to be considered playable, but resolutions don't? Is Ultra at a lower resolution really better than High at a higher resolution? If that was always true, why do we spend money on top in GPU's, when we could just use 720p displays? Why don't dev's extend the sliders on their games to allow us to see the higher IQ settings that they currently hide, so we can do this now?
Am I the only one who realizes that IQ settings and resolutions are one in the same, and dev's simply give us the settings based on the resolutions most of us use?
What would you guys do if the dev's removed the Ultra settings they have now (labeling the current medium or high settings to Ultra)? Would you complain about a drop in IQ, or be excited that your 4K resolutions can be played on a single GPU?
What if dev's give labeled the current Ultra settings to medium and gave us access to settings way beyond our current Ultra (they exist within the games, they just aren't exposed to us)? Would you lower the resolution, or lower the settings?