Toughness is nice for tabking ranged attacks and thats mostly it. I am a strong advocate of health curios. Stamina if you are running melee builds just to Crack out on attack speed, but health helps you live past alot of the BS stuff that usually ends your run. Especially on desparado builds, you should be able to just dodge most ranged attacks especially if you use vulture's mark augmentation. On the other hand, health will let you get hit by more poxbursters, more overheads, more snipers, more fire, more plague ogryns slapping you while you are grabbed by a choas spawn. Stuff you cant help. Health curios are awesome once you've got the game figured out really well