the dark suit ROCKS in terms of both aesthetic design and lore.
that the Luminoth's earliest ventures into combating the Ing involved the study, harvest and approximation of dark world energies and materials into a suit that is made to better withstand the opposite and thus light world degrading nature of the dark world over their original gear.
Honestly awesome lore implications from a simple description.
That the shoulders look like super sized filters, the departures in the breast plate design and various detailing, along with muted but awesome color pallet, mean the dark suit just HITS different visually and will always be regarded as a stand out suit.