Are defilers strong in Starcraft

Yes defilers are a really strong if you use them the right way. his abilitys are very helpfull For example dark swarm is really helps because it protects you from most long range attackes but the bad thing is that only meele or close range lke zealots DT,lings,firebat can kill units in a swarm cloud. but its helps attack bases because the bases are always well defended in most cases by long range untis like tanks or bunkers filled with ghost or marines also photon cannons. The ability plague is also pretty good. It sends a plague out and it slowly takes health away (also effects buildings). toknow if you got a unit with plague, look at them. If they are covered in a red "thing", then they most likely have it. Another way to chack is to select the unit and see if their health slowly goes down.