I have a DeepOutdoors Matrix LTD (same as the Matrix, but with the elevated D-rings). It is a nice and super comfortable Backplate with loads of attachment points and adjustability. I know several tech divers and even more rec divers who use it and love it. On the other hand, it is expensive and a little complicated compared to a simple Hogarthian harness and Backplate. The double waist attachment was overkill. I haven't used mine since I started cave diving.
I haven't gotten around to selling it yet. PM me if anybody is interested. It only has 10 or 15 dives on it. Size L/XL. $275.
I haven't used the Black Fusion wing, but I have used the Element, the Covalent, and an older 40lb DO wing. They are solid and well made, but I tend to prefer other designs.