Personally, I find Zubrin's personality so grating that I turn him off despite the good ideas he has proposed. He comes across, to me at least, as a zealot with a "my way or the highway" attitude. Sorry, but when you're talking about a massive undertaking like a manned Mars mission, building broad-based support is critical. I think that, in the end, he may well be on the outside looking in when (not if) the nation commits to sending humans to Mars. By that time, he may have alienated too many people. If he isn't careful, Zubrin might go the way of the brilliant Aussie pilot Sidney Cotton, the father of WWII aerial photographic reconnaissance. He proved his ideas were right, only to be pushed to the sidelines by the establishment. BTW: his original spy plane apparently is still for sale!

As I've written before, I believe that an incremental approach is the one with the greatest likelihood of success for getting to Mars. I base that on a 100 year history of flight test and a 46 year history of space exploration. Swinging for the bleachers can please the crowd but you'll strike out more often than not. In this case, a strike out results in a failed mission and perhaps a dead crew.