Actually, you should answer two questions here. What do you need more: preventing damage or preventing the other effects of the enemy cards? And would a random card from your deck be better than the enemy attack? Both answers depend on your deck and the situation. A dwarven control wizard (especially a member of 3 wizards team) may prefer Toughness, especially versus enemy warriors, since he needs to survive just one attack - you're going to teleport the enemy away after it. The mage would definitely prefer a card from his own deck since Winds Of War or Whirlwind Enemies are the best cards he can get. A dwarven warrior should prefer Duck, though, since he has a lot of hit points and can survive one attack, but will lose if he gets encumbered or teleported. He may have a lot of great cards in his deck, but most of these cards would be unusable if he would be unable to get close to the enemy. I'd prefer Duck for my warrior even at close range, since every attack counts, and the enemy may simply lack the weak attacks! But even if the enemy has them, he still loses the tempo trying to trigger my Duck. He's hitting me with a weak attack - I hit him with a strong one If my warrior has Mass Frenzy (and he usually does), even the weak attack wouldn't be weak in response. Plus, Duck is invaluable when the enemy tries to bash you away from the victory area or activate All-Out Attack. Would he play a weak attack to waste All-Out Attack, or risk wasting a strong attack to my Duck? Toughness is inferior here, since I need only attacks, and they cannot fill more than 30-40% of my deck, and some of them are going to be weak too.