Not sure what the first one means. Do you mean like you die for one day then wake up and you have a normal length life?
Are the life lengths guaranteed, or might I still get hit by a bus / get cancer / go mad etc?
I guess I'll opt for dead for a day so that I can release a load of books about how I met god and make millions from bible belt types.
Would you rather punch a nun on the arm for no reason, causing her to be so upset she renounces her faith - and nobody knows you did it, or would you rather have everyone think that you go around punching nuns on the arm for no reason, but you dont?