Question about 1080p/1440p gaming on a 4K monitor [Build Help]

Hi all, I know this isn't really asking a question about a whole build for a new pc. But I'm looking at buying a new 4K monitor for my new PC. Having a GTX 970 means that I probably won't be playing too many AAA games at 4k resolution with high settings. So I was wondering what kind of issues, if any, would arise while gaming in 1440p or 1080p on a 4k monitor. ie if there is any loss of quality or distortions i should worry about since i'm not running them at the native resolution. The monitor i'm looking at is the Samsung U28D590D if thats any consolation.

Thanks in advance