I'm not American but I have always followed American Politics.
Whether or not Romney is a decent man is not the issue. Would he make a good President? The truth probably is that he would be okay, within the limitations that the job imposes, but a victory for him would see a shift in political emphasis more in the direction of Republican thinking.
I have no empathy with that ideology as currently espoused and would consequently prefer to see Obama, disappointing as he has been, re-elected.