Mizuno concentrated on producing the BEST irons for years and weren't taking the driver market seriously until they decided to launch the MX500.
They are playing "catch-up" in the driver market, when compared to other OEM's.
Since then, their driver offerings are getting better and better - I currently use the MP600 and LOVE it!! The MX700 is getting rave reviews, and I can't wait for their next offering.
It is a paradoxical but profoundly true and important principle of life that the most likely way to reach a goal is to be aiming not at that goal itself but at some more ambitious goal beyond it. - Arnold Toynbee