I wrote off Mars decades ago. It wouldn't be useful as a base for asteroid mining. It could support a fair number of monasteries and science outposts, maybe a Plymouth Bay Colony now and then. But look at Venus! It could be cleaned up, spiffed up, and marketed as the New World, the thing America was supposed to be except this time for real. Venus is our twin, you know.
Understood, however, we must walk before we run. Mars will be our training ground. As far as cleaning and spiffing up Venus.....well, that sounds like a HUGE amount of terraforming. If we could normalize the atmosphere, what is the predicted surface temperature supposed to be?