I have not hit with any of the Babolat racquets. I have read that they are generally a stiff racquet. Is the AeroPro Drive Cortex a stiff racquet? Have users had a problem with a sore arm from using this racquet? How would the stiffness and comfort compare to a nsix-one 95 16x18? I primarily play from the baseline, and it sounds like the AeroPro Drive Cortex is a very nice racquet from the baseline.