PS
You notice Zubrin included a lot of praise and support in his article compared to his criticism. I think he's trying to voice a difference of opinion without offending and he truly feels positive about those things. At the last convention when we got word about the large CEV was, his response was something like "well we got what we need for a Mars mission, but it's a lousy lunar mission architecture."
I think Zubrin's technical arguements are accurate with the key focus being beyond the ISS. Griffin is factoring in the ISS and political considerations. Start with different requirements and you will end with different solutions.
Regards,
Mark