One thing I'm not liking from what I read is that the Survival mode is not the same as Harcore mode.
Survival mode is the highest difficulty setting in the game and it only effect that your health doesn't regen when waiting.
You have to use stimpak,Doc,food or bed to get your health back up.
Eating and drinking is not mandatory it seems hunger and water managment like in New Vegas is not in the game for SS,the closes thing of management is gone towards settlements.
If you played Shelter that what the settlements represents,you have to have water,food,electicity to keep your town happy.
I really hope is not the case but we will have to wait and see.