I do well with the Eviscerator on my Krogan Vanguard. I've been meaning to equip one of my caster classes with the Eviscerator or Scimitar to see how it works. I think the Revenant might be better for my Krogan Soldier, but I'll try it out once more. That said, I've been thinking of abandoning some the Krogan's melee power and taking some points of Carnage... with the changes to fire explosions, it might be more worthwhile.