TSC55 has 2 * 18V batteries, I've read it's more powerful than the TS55. I have an HKC55, which has only one battery, and does certainly at times feel underpowered. The FSK rails are very convenient though, and it can also use the FS rails - which I like for rough cutting sheet goods for construction projects, because my TS 75 is big and bulky. I would not use it on sheet goods destined for cabinetry, because in my experience the TS75 does give a more refined cut.