Dave Dugdale of LearningDSLRVideo made the video above that shows where the differences between H264 output and Magic Lantern’s RAW are. A Canon EOS 5D Mark III (price & specs) was used. Dave says:
The real noticeable difference is when you really push and stretch the image, for instance here a shot with both somewhat similar settings and they both looks pretty good, but once you start to add saturation or really push the levels all over the place check out the banding above the mountains and look how the clouds are starting to fall apart image wise.
So you can push the image to make it look like the camera has more perceived dynamic range by stretching it, but even with raw you can only push it so far, but you can push more than the h.264. For me the new Black Magic Pocket Camera is very interesting because it appears with will have a nice wide dynamic range and it shoots raw or to a editing friendly codec like ProRes so can perhaps push the image even farther because of it’s actually larger dynamic range.