Myrmourn Banshees

I have finished my Myrmourn Banshees for my Nighthaunt army.  I have used them a couple of times but so far they have not done much.  I see many players are running 12 of these and they might be more useful in a large unit.  The models are really amazing.  They are some for the best on the Nighthaunt line which is filled with amazing models.