Mars is worse, you require radiation shielding due to the lack of magnetic protection, you need damn near spacesuits anywhere but the bottom of the Valles Marineris due to the functional lack of atmosphere, and the dust. Mars is a wasteland, and a waste of effort.
Making things withstand acid isn't hard, we don't do it as much because our atmosphere just burns a layer of oxidation onto everything, and acids are less common. If getting stuff to survive ph extremes were a problem, batteries wouldn't be a thing, I certainly wouldn't feel comfortable putting them on (or in!) my body at the rate we have and do.
Assuming you had a breathing filter and an umbrella you could stand on the porch of an aerostat floating in the soup we call Venusian air. We could use current technology and have habitats on Venus right now, tons of them, upper atmospheres are big places, especially when you have way too much atmosphere like Venus has.
We will never, in our lifetime, see a point where you could be anywhere near unprotected and survive on Mars, barring anti-aging, full conversion cyborgs, and the like. There are exactly three regions in the solar system with some combination of solid ground and 1 bar of pressure: Venus @49 km, Earth @0 km, and Titan @~0 km.
Titan is far too cold, but fascinating nonetheless, Venus has annoying rain and we don't breathe pure CO2, but oxygen is a lifting gas there, and we're in the last region as we speak. Living on Mars is BARELY easier than living on the Moon, except you have to descend much further into a gravity well, and travel much further, for no benefits beyond "we went there", which has value, but not much compared to "we are living on another world and can remain there indefinitely" like Venus air-colonies would offer.
Though, making humans out of all that carbon is silly, what you want to do is make diamond processors and upload into them.
Re: Dorsidwarf, You have the same amount of atmospheric protection 50km above Venus as you do here, how often do you go underground for solar storms? Never? Ok then. I will repeat my earlier point though: oxygen is a lifting gas on Venus, if you filled a balloon by exhaling into it and let it go outside your aerostat, it would float away.