I found this cool video comparison between the Sony A7r and Sony A7s.
I'm not sure why, but for some reason, 99% of all video reviews are people comparing ISO performance and rating the camera based off that. If you're doing real production you're going to use some form of lighting to hopefully keep you from having to shoot at an extreme ISO.
Nobody really compares sharpness, or color depth. The most important thing to me is how well the image holds up when color correcting. It seems if you want to use your camera to replace your night vision goggles, then the Sony A7s might be for you.
Sony A7r vs Sony A7s Video Comparison
Now looking at these two comparisons, the Sony A7r looks pretty good. It's still very sharp and has great detail compared to the Sony A7s. That's something I've noticed when shooting video with my A7r. I really like it over my 5Dmkii. Because of the lack of a highpass filter the image is much sharper, which was one of the biggest draw backs with the Canon 5Dmkii and 5Dmkiii in my opinion.
If you want to learn more about shooting video with the Sony A7r, or A7 check out my video guide.