posted on Aug, 6 2003 @ 10:01 AM
Water and atmosphere are, as I understand it, the main reasons. The Moon is fairly mineral-poor, meaning most resources would have to be shipped in.
If Mars proves to have water, it means some terraforming is possible and colonization is more likely.
Other factors include health. The moon doesn't have a magnetic field and has a low gravity. Mars, with a higher gravity and a magnetic field would
be a healthier place to live.