one of the most informative charts in Wishon's "Search for the Perfect Golf Club" shows what a swing robot which hit the ball dead center at a swing speed of 90 mph did with different driver lengths:

Driver length = 42 inches, ball speed = 133.0 mph, carry distance = 209.7 yards

Driver length = 46 inches, ball speed = 133.8 mph, carry distance = 211.0 yards

Why in the world would an average player like me attempt to hit a driver longer than 42 inches? You had better believe that it is exponentially more difficult to hit a 46 inch driver dead center than it is to hit a 42 inch driver flush...for a gain of 1.3yards!! What is the risk reward ratio?

Guess what my next driver length will be?