Defiance is incredibly useful also. The 25% extra hp is awesome when you wanna eat those hits, and the damage reduction isn't that painful because as Parn said, tank damage output is subpar and shouldn't be a focus (though I went all str for my bonus attributes heh heh). And the crit bonus and healing bonus I get while Infuriated is worth the neglected 25% damage penalty. Solo play, I may leave defiance off just to kill shit faster but party wise it's always on.
Now if only the dps nubs would stop attacking indiviual targets that still hit me, my poor healers would be so much happier not having to heal damage from 3 mobs at a time for every encounter.