Yeah. Mars is important, but testing stuff out where the ride home is a couple days instead of months/years seems a lot more sensible.

Sure, the Moon offers different challenges in spots, but it'll still let us validate things like growing crops, water reclamation, robotic construction, etc. with the ability to pop home if it all goes disastrously.

I agree. Both the Moon and Mars have a huge amount of sub-surface potential living space.

I think a long term colony on either of these worlds would be much safer below the surface where it would be shielded from cosmic rays etc.

If we can learn to build 'ant colony' style habitats on the Moon, we ought to be able to do the same on Mars once the cost of travel becomes lower.

Robert Zubrin has discussed the "moon first" strategy, and has made the interesting observation that many of the pro arguments come from entrenched space industries looking to make a buck on existing hardware. The argument being "we already build parts to go to the moon, so let's just do that."

Personally I would love to see both outcomes. But given a limited budget, going to Mars has the advantage of providing a (admittedly risky and uncertain) possibility of extending the survival of the human race, where as going back to the moon seems to provide more indirect benefits.