To me the advantage is not increased cooling...it's maintained cooling with reduced noise. When I finish the one that I am currently constructing (made of acrylic...pretty sweet so far) and strap a 80mm Panaflo H1A on there, I will be at 1 CFM more than the Delta Black Label and about 11 dBA lower in noise. I won't have the infamous whine of the Black Label either. I have heard others mention another advantage due to the fact that it elimates the dead spot in the middle of the heatsink that is created by the fan hub. Since the middle of the heatsink is the place you want to cool most I think there could be some serious advantages.
Eric