I would much prefer someone who has expressed a position, then after learning more about the subject adapted that position to bring it into line with what was most effective.
I am not saying you should support, or even like Mitt, but evolving positions on matters of public debate are not in and of themselves evidence of bad faith or a character defect. People in public life frequently must make a statement or take a stand on the spur of the moment and then later have to adjust that stand based on new information or being convinced the stand or statement was simply not the right.