I have been using BG66 on all my rackets for the past 1 and a half years or so. Recently, I got one of my rackets strung with Cyber Natural Gut 100 and to say that I'm impressed with it, is an understatement! From the time that I got that racket strung with the CNG100, I have also strung my other two Ti-10s with BG66. And the tension of the CNG100 is still holding extremely well while the tension the BG66s on the two Ti-10s have dropped very significantly. What I like about the CNG100 (that is different from BG66) are: 1) stiff (stiffer than BG66) 2) holds tension well (better than BG66) Does anyone out there know of any string/gut that plays close to the CNG100 or have the characteristics that I mentioned above? ie. like BG66 but stiffer and holds tension better. Thanks.