I really like Wilson US Open balls, and Dunlop A player balls, but I can't stand balls such as regular Dunlops, and Propenn Marathon. Those balls seem to fly and bounce extra high. I am 16 years old and I play high level USTA usually. Last few tournaments with us opens I played outstanding, and won a level 3 and got to the finals of the other. Just last weekend they were using Propenn balls, I practiced with them the week before to prepare for the tournament. In the tournament I won my first two rounds but struggled with kids I would usually kill! In the backdraw I lost to a kid who really is not very good. I feel like I struggle with these balls more than other kids, I play like a completely different person, not swinging out on the ball, and being tentative just so the ball won't fly out on me. I'm curious to see if anyone else has had similar problems.