One could argue that the most important component of one smartphone is the display. It dictates the size of the phone, for one. An awesome chipset won't help much with gaming on a tiny, low-res display. And such a display will prevent you from properly enjoying the photos from even the best camera. But what makes a display great? That depends on what you need. 120Hz refresh rate is a new feature to boast but it is yet to prove itself a vital feature. Something more basic like contrast ratio or sunlight legibility is a good place to start. There isn't a single "best" display, however....
Source: https://www.gsmarena.com/weekly_poll_what_makes_a_great_screen-news-28415.php