I tried the O3 Speedport Black after hearing that the Bryan brothers had switched to thes frames. I'm a 3.5 - 4.0 player and was looking for a frame upgrade. Wow was I rewarded with my choice! These frames are quick and responsive. I found that I got a ittle more pop on my serves, overheads and also am able to get my racquet in quicker position for volleying. I haven't felt to many mishits on my groundstrokes. Although there are two stringing options with the additonal insert supplied, I've been sticking to the Speedport stringing configuration and haven't been disappointed. I've just recently purchased my second frame and I feel quite content with these for the time being. Great job Prince and thanks to Golfsmith for stringing it to my specificiation and getting it to me without any hassle. A great purchase all the way around!