Q:

Venus vs Mars for colonization

Why is Mars getting so much attention vs Venus, which to me seems like a much more attractive option, in regards to habitability.
I've read that the upper atmosphere of Venus has the most Earth-like conditions  in the solar system, also terraforming seems pretty straightfoward.

Mine CO2, Water (from sulfuric acid), and necessary "fertilizers" from the atmosphere
Mine acidic salts from the surface to make more water
Continue until temperature lowers.

The ease of high(er) pressure environments vs low pressure environments in regards to habitat size, redundancy, and safety in general.
Also the propellant needed to land on the surface of Mars vs the near zero amount of propellant needed to deploy vehicles in the atmoshpere of Venus.
Not sure if this is allowed but Convince Me 

A:

The reason Mars gets more attention than Venus is because we could walk on Mars. Our current technology can handle Mars. Venus on the other hand everything dissolves in a few hours from the heat and acid which makes it a terrifying planet to visit. 
But on the subject of terraforming. Terraforming is still very much sci-fi and far off from any fact. We are talking about resource allocations on a planetary scale. But I have been looking at both and I too agree that Venus is more terraformable than Mars. Unlike Mars which has a litany of problems to overcome, Venus has just one, it is too hot. 
But geologically and chemically Venus has more favorable conditions than Mars. 
But for a species that is currently having a heat crisis of its own homeworld, I think we are far off from being able to fix that. 

A:

Leaving aside the terraforming question, having a floating habitat is non trivial since pretty much the only thing that is earthlike at the proposed altitude is the temperature. The pressure is very close to the death zone, the winds are cyclonic and up to 100m/s and the atmosphere contains sulfuric acid.
This can work for a scientific mission where you arrive, deploy a limited lifetime balloon and abort to orbit when resources run out, you get blown into a cyclonic region or anything else goes wrong but a permanent habitat has to persist hopefully forever in that environment and becomes a lot more complicated, where the need to remain afloat at an altitude approximating 18000 feet on earth while surviving turbulence means that your weight will be critical (think living in an RV/caravan, not Bespin mining station).
There are some things that will kill you on the moon/mars but not Venus (lose of power to heating/cooling, and leaks will be slightly less urgent) but you also do not have handy access to a surface to keep spare parts on, mine from, bury your reactor in or just to keep your two domes in the same position with respect to each other.

A:

I agree with some of the comments, terraforming should not be considered a serious target at this early stage of solar system colonization. 
Both Venus and Mars have their problems, but what make the real difference is our lack of experience in missions that are not surface-based, since on Venus we should colonize the upper atmosphere layers. With Mars we can reuse what we learned from the Moon. 

