I used the PST (non-GT) for two years. Had the same problem at first getting speed on first serve, then something clicked and it became the best serving racket on first serves that I used during that time (tried a bunch of others, but always went back to PST for league matches). If you hit a hard spin rather than flat you'll get a ton of action on the ball, even heavier than a flat serve for whatever reason. My two complaints with the PST were maneuverability at the net, and the second serve. For some reason, maybe the woofer system, it didn't feel very accurate on second serves, and I couldn't figure out when the racket was going to grab the ball. I hit some awful second serves that spun into the middle of the net. Didn't happen with the other rackets, and hasn't happened since. The best serving rackets I used during that time were the MGPP, and the K95 16x18. The MGPP hit great flat serves, didn't spin the ball as well as the PST, but I never double faulted with it either. It was actually a TGK238.2 that I got rid of, unfortunately.