Depends on the state from which the Governor came from: A California, Texas, Florida, or New York governor with the huge economies to deal with would probably have the edge over Senators who lack executive experience.
On the other hand, a Senator with the large-scale operations would probably have an advantage over a West Virginia or Wyoming governor.
Toss-up.
I'm not sure I buy it.
In a small state, such as mine in Rhode Island, the state officials are much more grounded and knowledgeable about what's going on at the local/family/individual because of its smaller size and therefore more likely to make targeted policies that actually work (as well as actually getting to know the entire state).
Whereas in a bigger state you're more disconnected, which would be true for the Presidency but it's a weakness and something Presidents always have to fight, to learn how to stay connected to the ground level while in elected office.