So if we are simply going based on Senate experience, McCain wins it hands down.
I don't know that is necessarily true. You could be in the Senate too long. Got too cozy with Lobbyists. Degraded your core positions to the point of going 180 on all of them. Perhaps been a member of the Keating 5 scandal.
Experience can be a good thing but there's also that old thing about absolute power corrupting absolutely.
It's a combination of enough experience to get started. The intelligence and research skills to pick good staff and make informed decisions and not the least of all the temperament to be calm steady & rational.
That's Senator Obama.