Christie is more tested than Rubio? Don’t know about that. They have both been through exactly one statewide campaign, Rubio in a bigger state with a bigger population and many more TV markets. I wouldn’t pick Rubio FWIW, but her argument is garbage. Doesn’t really matter because Romney will not be getting my vote either way.
Governors have more administrative experience than Senators. That's in the nature of the positions. So someone who's been Governor for two years has more experience than someone who's been a Senator for one.
Christie's also older, and in Ann's eyes, his earlier experience as US Attorney probably trumps Rubio's in the State Legislature. Either would probably complement Romney, appealing to groups Romney would have a harder time with.
Kyl, by contrast, comes across as pretty white bread, more like Romney than different. No ethnic appeal.