My style of riding is based on carving. I have been using the Driver X since it came out because it is the stiffest and most responsive boot I have tried. The 2014 version is the best one up to now. They brought back the responsiveness and stiffness of the 2009 version, but with a better progressive flex.
For the last 3 years, I have also been using a heat molded liner (old version Scarpa) instead of the stock Burton. Million times more comfy. Also added a powerstrap to the top of the liner. Made these the best boots I have ever owned in my 35 years of riding.