The Gown of Spiritual Wonder is a total upgrade from the Primal Mooncloth even if you take into account losing the set bonus, which by now should already be lost if you are raiding above SSC.
GoSW not only has more stam (which isn't incredibly important) it also provides more int and spirit that makes up for the 10 mana per 5 you are losing. Even after filling in the gem slots with epic gems the GoSW still comes out on top.
This ranking/rating should be fixed.
