First, it excudes half the remaining Republicans. (Maybe that's how Hew Hewitt intended it, but FReepers know better.)
Also, it conveniently omits a number of major policy questions that neither "front-running" candidate wants to talk about. I wonder why.
Here is a chart that makes up for those omissions and puts things in proper perspective.
That chart is also deficient. For one, it lists Romney as against abortion. Though he says he is pro-life, his actions have been decidedly anti-life. Offering health-care seems wrong too. As does the immigration question, since he did nothing to act against sanctuary cities in his own state.