Antarctica is impossible from a technological stand point (energy, temperatures and seasons), unless of course you want to live with Hitler and his scret base in antarctica, maybe he can take you in his Hanebu to the dark side of the moon (which is not dark actually)
But anyways if you can set a permanent base in Arctanctica, setting one in Mars shouldn't be an issue (apart from getting stuff to Mars )
Antarctica is not impossible at all.
Mars would not be impossible either, but it would be a lot harder.
Apart from getting materials to Mars, there would be problems with food and water supplies. And of course, we must not forget the problem with oxygen. And the risk of meteor crashes is much higher thanks to its thin atmosphere. Oh, the atmosphere would also be a big problem since it doesn't stop much of the cosmic radiation. So simply, it would be a LOT harder.
So, lets not mix apples and pears, shall we?
