Mars may be useful as a base but humans could not live there without major modification to how we grow and develop. We simply weren't designed to live in such low gravity the way we are now.
Also, the kind of work required to terraform the planet to be livable would take many thousands of years. Not saying that's a reason not to start, our sun will shift it's 'goldilocks zone' towards Mars at some point.
Mars also has a near guarantee of a cataclysmic apocalypse scale disaster just waiting to happen. It's Moon, Phobos is either going to crash or break up into a ring in about 50 million years. You don't want to be on that planet when that happens (ok, so that's so probably 300,000 times how long us
homo sapiens have even existed but still
As Mars is now, I don't see the point. It is sterile. Imagine being there right now. You would think some guy in a cave in an inhospitable desert on Earth is living in luxury. Well you would have all of a few seconds to think of that before you suffocate in the most bitter of colds
There is one thing we are just going to have to suck up and break the stupid COSPAR Planetary Protection Policy. It's time we seeded the other planets while we still haven't blown each other up or succumbed to our own stupidity and dying out from a preventable pandemic.