Of course, there is an element of smoke and mirrors here. A lot of PS4 Pro's 4K rendering techniques don't actually resolve a full native ultra HD framebuffer, and yes, there is a resultant cost in terms of the quality of the presentation. The question is the extent to which you'll notice the downgrade in real world conditions. Stack up a native 1800p image up against a full 4K framebuffer on an ultra HD screen and the difference should be obvious. Certainly, when you look at the zoomer images on this page, the softness on the lower resolution image is apparent, though perhaps not as much as it should be. However, whether we're talking about 27-inch or 32-inch PC monitors, or large living room UHD TVs at normal viewing distances, the extreme pixel density of the displays makes the difference much more subtle in real world conditions.