So here we have a side-by-side demo from the 'Elemental' tech demo, showing just how the PS4 stacks up against a PC. If you "look closely" (/biased) you might spot some very subtle differences.
The demo clearly shows the gap in horsepower between the two, which to be fair isn't all that surprising. Surprise or no surprise, it's still good to get to see the new Sony flagship in action.
Early on in the winter scene, you can see how decals, material reflectiveness and even shadow resolutions are stunted on the PS4. Moving into the cave area, what is on the PC subtle differences in silhouettes among the shadows, on the PS4 these dark blacks are almost completely washed into one another. Looking at the frame of the crack in the wall, what appears to be a tesselated rock structure is a lot less nuanced on the PS4.
We proceed onto a close-up of a dead Sauron-looking guy. At this point the PS4 starts to stutter profusely, even with it's vast allowances made in removing reflections, refractions and depth of field. At least it appears to output the same texture resolutions as the PC, but it should be noted that they're low to begin with. As we zoom out on the fallen king, once again, the PS4's shadow rendering makes all the nuances disappear in a black mess, as well as a somewhat simplified air particle rendering. If you look to the bottom left corner, you wouldn't even be able to tell that it's a shield on the ground if you hadn't seen the PC version next to it.
The following scene, looking at some pillars and a gate, is probably the one that suffered the most. The scene is a grey mush on the PS4, with a lot more nuances showing on the PC, presumably due to the interpretation or simplification of the volume of particles in the air. Both of them disappoint in anti-aliasing, however, this may be a fault of the engine. (Or because the PC version is running in lower, I.E. TV-level resolution for relevancy next to a PS4) Looking at the floor, where the sunlight meets the shadow, the PS4 seems to be drawing a *gasp* stencil shadow on the ground!
The gates blow open. Forth from it's mouth, grey porridge pours. Well, on the Playstation that is. It's PC counterpart seems to have drawn snowflakes instead.
I could continue, but I think I can safely lead the rest up to you, as the differences only become more pronounced. To those who expected to be blown away by the PS4 (and with performance, not porridge) I express my deepest sympathies, but it should be noted that the graphics card of the PC in question costs half as much as the upcoming PS4, in all likelyhood.