For me is BG65 which i last used 6 months ago. I have been using it since i started playing badminton 3yrs ago. Find it is Stretchable? I can feel the dent in my strings when i smash. Give out a realliy loud 'BANG' and have a solid feel which i like. Durable too. Lasted 4 months. Tried Ashaway M5? Which loses power after 1 month of playing. Quite Durable. Broke after 3 months. Tried BG66 but finds it not as powerful as BG65 although people and yonex claim it to be a more powerful string.. Sound not good too. Lasted around 1 month+. Tried BG80 and finds it much like BG66. didn't feel any difference. Tried BG68Ti on 2 racketsbut didn't realli get the feel. Find it too stiff and dead.. with slices all gone out of places and no power.. smashes are fast but not enough feel and sound. Both string snapped in less than 27 days. Maybe i was trying too hard to get the feel. S$32 gone. Currently Using MicroLegend but yet to play my 1st game with it. will be updating soon. seems pretty powerful to me. What about u guys?