I've used both for a few years now and haven't noticed one significantly better than the other in my experience. Arda back order is becoming a serious issue though. I can't buy anything from them because none of it is in stock so I go to epic instead. Thanks!
They actually make cloth covered wig heads that more professional stylists use. If I wasn't on a time crunch I would have gotten one! I also hope I never make anything that will require worbla on a wig head ever again. This project was hard for me.