Mars is just a big dead rock really. The “self-sustaining tin cans” are the way to go IMO. We can learn how to do that in orbit around Earth (where aborting the mission isn’t automatic death), and then go colonize the asteroid belt, where the resources are just sitting there floating in space.
Mars offers: gravity, but the wrong amount. Air, but not enough. Sand and dust, but not the kind that grows anything, just the kind that gets in your filters. Also it is toxic. Not much magnetic field.
