I did some testing with nat's set on a trapper (3 ptopaz in arm). For me, this invloves basically trading in a claw, say bartuc's, treachery, and a 3 trap hat. This means you've lost +1 all and +3 trap. A loss of 4 +skills on your traps sacrifices about 1.5k max damage. In return, u get +50 res, 30pdr, and some mf (if u ptopaz as I did). No amount of toughness makes up for going from 6k without skillers to 4.5k IMO. I don't get hurt anyway.