In my opinion, this will give the Vikings a huge advantage. Farve was with the Packers for 16 years, so he knows everything about the offense and is has been playing against the green bay defense for years during practice. In high school, our QB changed schools and when we played him he knew everything we were doing, all of our audibles, etc.
Apart from the fact that the Vikings are already the fave, if I need to play catchup after the weekend, i'm going Vikings.