And the award for most pleasing grain structure goes to...

I shot some comparison footage on a rainy day. I used the same lighting for each shot. All cameras were set to ISO 800 and were fitted with the same 50mm Canon lens (except for the Red, which had a 50mm Nikkor AIS). I added a noise-popping curves adjustment.

Red One MX - Redcode 36, 4K HD, Red’s Chromatic LUT

Canon C200 - Canon Raw Light, C-Log2 with a Rec709 LUT

Canon EOS-R 4K - Internal 8-Bit C-Log, C-Log to Rec709 LUT

Canon 5Diii with Magic Lantern Raw - No adjustments, just enlarged from 1080P to 4K and converted to ProRes4444

My big discovery is that the 9-year-old Red One MX has the most pleasing noise structure of any of my cameras. This old sensor continues to surprise me.