I'm not sure, Gangrene was a mixed bag in my opinion. It was still great, but there were one or two tracks that were a little boring. Of course boring by Mirrorthrone standards is still great, but I do think Carriers of Dust was better.
As for his other stuff...I've not heard Unholy Matrimony but I have heard Weeping Birth and I didn't think all that much of that material. Maybe my expectations were too high, but it really didn't have much of the terrifying brilliance that Cochet continues to convey in Mirrorthrone.