For people under-estamating this item, take it this way:
Shadow Mantle is basically your fourth line of defense. Basically, after your Evasion, Parrying, and Shield, there is a chance that the damage will be zero'd. This piece is an amazing piece for any tank, including ninja and especially paladin.
Very good pc for Dancer imHo... {Fan Dance} + Dmg Null + High Eva + Self Cure bombs (+20 VIT on Drksday). Great pc for a Dnc... lil hard to get however 8P