Why is it always Mars this, Mars that?
In every way, shape, and form, Venus is a better target to explore than Mars.
It is closer to us, it has a thicker atmosphere that allows actual sizable payloads to be landed Unlike Mars
, it is closer to the sun with more usable solar energy, it has a habitable zone in its upper atmosphere that is the most earth-like environment within our solar system, it has nearly the same gravity as Earth, and there is SO MUCH we still don't know about Venus.
We could colonize Venus with simple aerostat habitats, essentially floating sky cities or zeppelins, which remain bouyant in the upper venereal atmosphere at Earth-normal pressure and temperature, with said habitats creating water, oxygen, lifting gas, and rocket fuel solely out of the H2SO4 in the atmosphere and power from the sun. We could use the increased solar flux to power orbital factories, smelters, and foundries, while putting mineral-rich asteroids into orbit around Venus for mining - a location where a mistake and planetary impact won't end humanity. We could even Terraform, in a realistic timeframe
the upper atmosphere to something that's breathable to humans, and then start seeding it with Earth-based life.
On top of that we can research an environment where a run-away global warming effect has taken place and see how that compares to Earth, and explore an incredibly alien surface with robots, possibly even performing tele-mining operations for materials and resources.
Anything we could do on Mars, we can do on Venus better.