I had been a projectionist for a long time (now this profession has died), and from 2000 on I had also been a digital projectionist. Until 2011, when automation finally killed the job, I used to compare my own stuff to the DCPs, side by side on the big screens, in the last two years also as DCPs, when easyDCP and openDCP became available. The largest screen was 78 feet x 32 feet (that's for scope, for 16:9 the width then was 58 feet).
First thing I noticed is that resolution doesn't influence sharpness to the expected degree. And it also doesn't influence subjective quality very much. In fact, an upscaled SD DVD ( anamorph pixels with scope-crop, really the worst way to treat a video) could be shown to a big audience, and (back then) nobody complained, the class-A hardware scalers made it look good. I know this is hard to believe, but we once had a festival with student films, ranging from DVD, BD to genuine DCP (a Red!), and the one best looking was a masterfully graded HVX200 short, played from SD DVD.
On the other hand, there was a way to know instantaneously what was film and what was video: Colors.
I know this comparison is only 8-bit, but I have to find a way to describe aesthetic subtleties here. With a camera like the GH2 ("Musgo"), for example, one would be well advised to fill the frame with detail, textures (resolution, that's the GH2s strength) and not with skies and other big areas of glorious colors.
Right now we grade for 8-bit, so 12-bit raw is *just* a bigger palette for grading. Color depth seems to add a new dimension to our video. It's fun to tear the, er, bloom off the images and to dive through the colors. Would it stand against an Alexa? I can't tell, really, but I'm convinced it would do better than many others.
I can't wait to see a DCP with the 12-bit preserved in my old cinema.