He's done a shitton more than she has, not to mention he's dedicated his life to public service. She's a former sportscaster from a town of 7,000 people who rose to mayor because other people had to quit, and then she did a year and a half as governor of a state that is pretty close to Russia.
I don't even really care about the lack of experience, it's that McCain picked her ahead of dozens of other more qualified people because he needed the combination of Hillary supporters and crazy religious ones.