Hey, I need some advice, because im horribly confused. I ordered two Racquets from TW to demo, the Pure Drive OS, and the Prince O3 Hybrid Shark OS. I start playing with the O3 hybrid shark, some weird things happen. The ball goes absolutely nowhere when I hit a normal groundstroke, so i compensate my swing and the ball goes flying to the fence. When i hit a block shot, the ball also goes flying to the fence. My first serve goes nowhere either. The racket hurts my arm a little as well. This confused and annoyed me alot. I pick up the Pure Drive OS, which is VERY similar to the Hybrid Shark in terms of weight, swingweight , and supposed to be more powerful. My groundstroke is fine, most of my shots are going in. My serves go in too. I look closely at the Hybrid Shark OS and find out it is strung with Gosen Polylon 17 string, whereas the PureDrive OS is strung with Wilson NXT Max 16. Could this be the reason the Hybrid Shark is acting so weird? If so, how would I properly evaluate my demo if I dont play well with polyester strings..?