At a recent preview event for The Witcher 3: Wild Hunt those in attendance were able to see the game running on all three major platforms (PC, PS4 and Xbox One), and while there Gamestar was able to examine all three versions.
Here’s a quote from the German site – Google Translate
“In the duel console PlayStation 4, meanwhile, has clearly ahead of the graph. Although the textures are a bit more blurred than “high” PC details that falls within the normal TV-distance but hardly noticeable. In addition, the witcher adventure runs on the PS4 in 1080p – but only at 30 frames per second, which did not bother us.
“On the Xbox One Geralt goes also with 30 fps on monster hunt, but only in 900p, the textures also seen slightly more washed out than on the PS4. However, polishes CD Projekt own words yet on the Xbox version, maybe you can still screw up to 1080p, but you would not promise anything. Stand now is the PS4 image the sharper and stronger color.”
As the quote above suggest the game is still being optimized, so thing could change between now and launch.