I just bought a Mizuno Fortius 90 and had my first session with this racket. It is a 6U, medium flex, head heavy racket, and I had it stringed at 29lbs. To my amazement, the racket is a joy to play with, I can easily generate power relatively easy on this racket and due to its super lightweight, about 72 to 74g, I can maneuver it to do all kinds of shots with ease. My usual racket is Li Ning N9II and I played only double now. As compared to my LN N9II, I feel the smashes coming from the Mizuno Fortius 90 is faster and more powerful. Really love this Mizuno Fortius 90 racket now.