Venus is interesting. While the surface is extremely hostile, the upper atmosphere is maybe the most similar to Earth-like environment out there in the solar system. At about 50km up in the air, the air pressure is about 1 Earth atmosphere, and the ambient temperature is about 20C. A 80/20% nitrogen-oxygen gas mixture is buoyant too at that depth, so a balloon filled with breathable air will just float. A rupture won't cause explosive decompression like it would on Mars either. In addition, the gravity one would experience is only very slightly less than that of Earth, and the large atmosphere also provides some shielding against radiation.

Mars doesn't have these perks. Mars is cold, really cold, with only 1/3rd of the gravity of Earth, has practically no radiation shielding, and any breach would cause explosive decompression and almost instant unconsciousness. On top of that, regular solar panels really don't work that well on Mars because of the extra distance from the Sun, while solar panels would actually work better in the upper atmosphere of Venus.