[Nasrudith]

I personally suspect the main reason for going above ground is morale and psychological essentially to have some sunlight and a view of the world they are settling to validate the purpose on an emotional level.

I am uncertain of the ergonomics of living spaces in artifical environments - I suspect even the experts are uncertain and even if they invested heavily they would discover design mistakes to correct in future iterations.

[bryanrasmussen]

I would imagine artificial sunlight would probably be preferable to humans in comparison to the far less bright sunlight of Mars - http://tomatosphere.letstalkscience.ca/Resources/library/Art...