I have not been playing tennis for the last 10years and I used to play with Synthetic guts. It seems there had been there are a lot of changes in the string technology. I got a set of Wilson NXT and really like the feel and bought some of the K-gut 17 but have not put them on the racquet yet. I then read about the X-1 Biphase and it's a highly rated string. I bought a set and put on my other racquet(Wilson Pro Staff 95). However, the string feels like, how should I say, no power? I hit the same way that I hit my forehand and single handed backhand but feels like the ball does not have the same power that the NXT has. I am probably a 4.0 to 4.5 player level. I used to play in high school tennis team and some tournaments. I feel good about my FH & BH swing. I had it strung at 62lb on both of my PS 95. So what am I missing or not doing right with this highly rated string? I feel a bit disappointed after reading all the reviews of this string. I hope k-gut will be better.