Corrosion is well understood and can be handled. Where else (outside of earth) can you find 1G, near earth temperature/air pressure, free energy (solar), radiation shielding, an atmosphere from which you could make water if not air, and a relatively short (6 month) trip away ?! None of those are on Mars. Combine with a skyhook/elevator and drones to fly below the clouds and there are plenty of opportunities for exploration especially of the Maxwell Montes (11km high!) and Maat Mons (highest volcano). And perhaps could become a base to explore Aten/Apohele asteroids.