This is a fantastic comparison, and mirrored a lot of what I found out when we did our own testing with the Helium, except we used a Sony F55 with AXS-R7 RAW recorder instead of the Alexa Mini. We definitely saw a lack of range in the highlights, and strange color shifts all across the board. Anyone interested in that test can find it here. http://zsyst.com/2017/02/f55-vs-red-helium-8k-vs-red-dragon-6k/
I think the Helium sensor will get much better as they develop better processing science for it instead of borrowing from the Dragon sensor.