Seeing them side by side in the review, at least externally the C4 really does appear to be nothing more than a carbon copy of the M1, a tabao-marketplace clone. While the internal layout is more customizable, these changes don't seem to offer performance improvements.
In my mind, if performance isn't improving the only reason to choose one over the other is (1) hardware compatibility or (2) looks.
With respect to (2), I think the C4 could differentiate itself a bit if it offered a more premium finish, something akin to the Ghost S1 or Winter One. This change alone would make it a premium alternative to the NCASE.
There are very few truly premium cases on the market. The C4 could fill in here.
Finally, while not addressed in the Google Doc, have you considered changing the hole pattern on the case? Ali mentions that removing the top panel alone drops temps something like 5C. I know that some Ghost S1 one users were able to drastically improve thermals by switching to a MetaCustoms fan grille which had larger, but still pleasing, vents.
