My last sub bruised silly easily so if I used metal cuffs on her she would have to wear long sleeved blouses and gloves the next day at work and she couldnt have that .
So I got some leathercuffs with metalchain between them so she got the "clinking sound" when moving her arms and legs which we both love. Also I got some velcro cuffs that are very easy to use and nice for fast release and if you want to change positions on her.
Rope is my all time favorite though. Wish I could do Shibari. ... (waiting on the book I ordered impatiently)