If you're buying a new TV over 50" or a monitor over 27", spend the extra $50–100 for 4K – the difference is visible. For a secondary screen, a budget laptop, or a kids' tablet, Full HD is perfectly fine. For content consumption on a phone? 1080p is indistinguishable from 4K on a 6-inch screen.
On a 65-inch or larger TV (especially at 4K native), 1080p content looks soft . The scaler has to interpolate 4 missing pixels for every real pixel, resulting in visible blurring or jagged edges. For home theater enthusiasts with 85" screens, 1080p feels outdated. Full HD Video
The term "Full HD" was coined to distinguish 1080p from 1080i. The "p" stands for , meaning the entire frame is drawn in sequence. Conversely, 1080i (Interlaced) draws half the lines at a time, which can cause flickering or motion artifacts during fast action scenes. When we discuss modern Full HD Video, we are almost exclusively talking about 1080p. If you're buying a new TV over 50"