Mortal wounds = no saves, no exceptions (except for probably someone has a stupid special rule) And yes, all mortal wounds are cheap if you don't have a points cost, but there is a cost to losing large numbers of models or of only fielding a small number (and then summoning) and losing a few models if there is a minor victory to be had. If you field a big army there is a risk your opponent will get to choose a sudden death option. Anyhow here find some Math AoS on how to get the most mortal wounds per model. I will serve: Jungle swarms. 0.27 MW per combat round per model (5+ to hit x 6+ to MW x 5 attacks) Threat range 6 inches + ~7' charge. Can your model beat swarmy? The ball is in your court.