RED vs Nikon D3S test was done in After Effects. The Nikon D3S footage was upressed to 4K with Instant HD plug-in. The frame rate conversion from uncompressed Nikon D3S 60p to 25p was made with Twixtor plug-in. No color correction and only basic keying with Keylight plug-in. The final result was rendered to a .tga file sequence and then scaled down to 1920×1080, mp4/H264 in Procoder to match the Vimeo standard.
Conclusion: The RED 4K material has more and sharper details but it is more complicated to key out the green screen.
4K, 320 ISO, 50mm f:2.8, K5600
NIKON D3S Settings
720 60P uncompressed via Black Magic Intensity, 200 ISO, 50mm f:4.0, K5560