Doesn't really sound like it when you bring up the ISS. You've got a huge behemoth designed to do a lot without the crew needed to do it. All serious manned Mars missions have a higher crew componant than 2 with a far more focused mission. Throw in the whole orbital assembly nightmare on top of that.

It also shows in your sustainability response. A habitat that can last for years is already a big step towards a sustainable presence from day 1. The most critical insitu resource is CO2 and it's available everywhere on Mars. The second most critical is water and it also seems to be relatively easy to obtain on Mars compared to most other places off of Earth.

I also don't think you really addressed the adaptability issue. Yes man has stayed the same product of 6 million years of evolution forcing him to become the most adaptable animal on the planet while robotics have advanced. We now have machines approaching cockroach capability. We may be smart, but I don't think we are anywhere near replicating our abilities in a machine. As awesome and worthy as the MER rovers are, a human would have gathered the same info in far less time and moved on and followed up. The risk and cost per mission is less with robots, the cost per unit of knowledge is more in my opinion and it has a huge opportunity cost in the sense that very little knowledge is gained about living on Mars.

The most efficient scheme is robotics combined with a human presence. Humans would increase drastically the efficiency of rovers simply by enabling them to move faster from point a to b and a lot of rovers can obviously cover far more points on the surface. The advantage in humans is in doing detailed research with rapid followup. If robots were better at research than humans we could just close down our graduate schools.

Above all else the key issue is whether you are interested only is studying other worlds or whether you are interested in humans living on them. Robots only makes no sense if you have any interest in the second.

Regards,
Mark