Playtested both Firestorm and Thunderstorm.
I'm very impressed with Firestorm, with a very good control/power ratio, nice feel, good spin and very comfortable. I actually thought the overall performance reminded me of ALU( non rough ), and it's my main string right now.
Thunderstorm is much more powerful, with excellent feel, but didn't find any increase in spin, despite the 10 sided/twisted shape. Very good for those looking for extra power in polyester strings.
3 matched Yonex Ai100 - B5E x Focus Hex 1.18