Sahara probably, better chance of running into a bedouin or something like that. And I'd know a little bit of what to expect and do. Not so much for the arctic.
probably the artic, extreme heat in the Sahara ugh atleast when you die from freezing to death you get very sleepy. Heat related deaths i only imagine would be like your being baked to death...i'd rather get sleepy and just die off than be zizzled to death like a stip of bacon.