What to expect with your first tail

[Mermaid Oshun]

I think they're saying its like a peddle that doesnt require much movement on your part to move it with a stiff one. A soft fin requires you move more to get it to follow all the way through. BUT you need more strength to push that hard fin and all the water. It boils down just to preference imo. Stiff with flowy ends is what I did for Yulia so it is hard but will look really flowy and wiggly on those long tips.