Man... 20 Scourges. Putting that into a list would be really, really weird.
My experience with them has been that they do alright as a versatile shooty unit that likes to hide in the rear. A while back someone mentioned using them as an aggressive front line squad and I like the sound of it. Arriving out of nowhere and blowing a unit away with shredders sounds pretty nifty.
On a side note, how do they compare to gargoyles? Ya know, those shooty nids with wings that tend to see more play than scourges?
Time for the grateful DEldar.