Not having ground is pretty dang tough. And Venus, since it doesn't have a very accessible ground, doesn't have many natural resources at all: only what the atm

Not having ground is pretty dang tough. And Venus, since it doesn't have a very accessible ground, doesn't have many natural resources at all: only what the atmosphere provides. Nitrogen, CO2, maybe some hydrogen if you can wrench it from sulfuric acid. Mars has/had a hydrological cycle and thus not only has accessible raw minerals, but many are concentrated to a useful degree. There's water ice, gypsum, salts, metals, clays, etc. Mars has abundant iron-nickel meteorites on its surface. As far as landing a long lasting robot on Venus, ABSOLUTELY it's easier to do it on Mars. Every robot landed on Venus has died within a couple hours because the heat is so great. You need an insane power source whose cold side is hot enough to melt lead and glow a dull red in order to produce enough energy to refrigerate your vehicle. This is possible but extremely difficult to do. There aren't a lot of materials that work at the 450 Celsius. VERY few plastics (Kapton for short duration), and even a lot of metals have problems. And the pressure is insane, too. It's like being in a supercritical CO2 autoclave. And on the surface, there's almost no sunlight and the windspeed is very low. The only feasible powersource really is nuclear (radioisotope and fission) for long-term use to run a refrigeration cycle. It's possible to use high temperature electronics, but the power requirements for those are extremely high and you're stuck with extremely simple digital circuits. Think 1940s/1950s electronics. Mars is just fantastically easier. Floating in the clouds of Venus isn't so bad, but again, no ground. I love the idea of sending a lot more stuff to Venus. But Venus is a hellscape on the surface and so you're stuck floating or flying indefinitely for long-duration things unless you pay a really high engineering price.