Here's a shot taken while rotating the camera at a medium steady rate (taken from a capture card rather than using the built-in sharing feature).
Considering the technique being used, I'm impressed with how artifact free the image appears in motion. From what I can see, this type of rendering has the most noticeable impact on thin objects (such as fences) but even then it simply looks as if it is part of the camera blur.
Here's the same area taken with maximum camera rotation speed. Motion blur is in full effect. If you look at the metal flooring you can see increased aliasing with larger steps but the image still looks good. Without the excellent motion blur it would certainly be more obvious.
I'd love to know just how many resources this technique frees up. It could be a real alternative to traditional rendering that would allow for a higher framerate without the massive loss in image quality associated with lowering overall resolution (which really only looks bad as a result of scaling).
Also, just for fun, here's a shot with the PS4 set to output at 720p. The system is downscaling the image so jaggies are minimized compared to what you'd get with a traditional 720p image. When blown up to 1080p it looks dramatically worse than the 960x1080 method they used.
Click on the images to see them at full resolution.