I will be testing the majority of the Polyfibre strings with the exception of Hexblade and Hightec. I have tried both TCS and Viper and will be getting Black Venom which many have touted and Rapid TCS and Cobra which I haven't heard much talk about on the forum. All strings will be strung on Babolat Pure Storm Tour GTs at 53lbs of tension. TCS 17 1.20 string - One of the first strings that I had a chance to try in both the 16 and 17 gauge version. Based on this initial test, I prefer 17 guage and will attempt to use 17 gauge or slightly thinner if 17 is not available. The first hour of hitting, the string felt stiffer than I would like but started to soften up after about 2 hours of hitting and became a comfortable string with a lot of pop and decent spin production from then on. The string has good dwell time but became a bit bouncy and springy after a couple hours of hitting. Viper 1.20 string - This string was one of the easiest poly to string and felt soft in the hands for a poly. After stringing the racquet, it only took about 30 minutes of hitting before the string settled in and felt really nice and plush. The string is neither harsh nor mushy. It had a very solid response and feel when making contact with the ball. I hit with this for about 1 hour and it offered good control, spin and good power. So far, I am liking the results from this string. Only question now is how long will tension be maintain and how long will this string last. Will update when I get more hitting time in. As a side note, I had the highly touted Tourna Big Hitter strung up as well for comparision and I preferred the Viper over the Tourna Big Hitter Blue mainly because Viper had a more solid feel when striking the ball. I felt better control with Viper than Blue while Blue did offer more dwell time. Spin to me was about equal between the two string but Viper definitely had a more solid feel. Tourna Big Hitter Blue was like stringing up Luxilon Alu Power, a pain. Of course, price wise, Viper is almost twice Tourna so if you looking for value, then Blue would probably be the better choice.