IMO All the marketing seems to be tellingly lacking of any mention of dynamic range. Largely because it looks like DR and ISO noise have changed bugger-all.
From the Canon USA sample images:
"EF 14mm f/2.8L II USM | 30.0 sec. | ISO 6400"
Look at the colour noise!!! What a disappointment...
For comparison, this is a SOOC jpeg taken with the a7R II: (Loxia 21mm, f/2.8, 20sec, ISO6400 - resized to same resolution)
If they could've improved noise performance and DR I'd have jumped back (when funds permitted) because everything to do with using
the camera is so much better on the Canon, but it looks like I'll be stuck in the Sony camp a while longer as I can work around its flaws for now.