I have made some comparison some time ago; h.264 with the best ML encoder setting 1080p (IPB, gop24, bitrate ~60-70) and 1536x640 raw upscaled about 125% I believe. It was couple days ago with a quite old build. I tried to grade h264 clip to look as similar to raw as I could.
In terms of general sharpness I would say it is the same, I was quite happy that resolution which gives continous shooting is not worst than best h264 setting. In terms of detail it is much much better. Leaves, grass, everything has more...details. And dynamic range of course is also much better, I could easly bring back the blue sky with some clouds (with h264 sky was white/grey). Colors generally are much better too of course.
So I would say that 1536x640 raw is better than 1080p h264 and it is continous. With the newest build even 1600x670 is quite usable, around 370 frames, can also go wider to 1680x630 and also have ~380-400 frames. I need to make such a comparison.