I like the challenge of getting the most out of the wood without deforming it, ie, without over stressing any part of it, with too much compression or tension. I think the set the bow takes (if any) shows this exactly...the perfect design for a piece of wood will produce the least set...
secondly, is the hand shock or residue vibration...I really dont like this.....if it has no set and no vibration its a winner.....Thats me anyway ( not that I've fully achieved this ..yet)
oh and dont forget beauty is very important too....3rd on the list
Dave