Well there are quite a few benefits to having a cordless track saw, the most obvious one is when you are working on site with no power to hand but you still want to produce splinter free cuts quickly. Also if you are comfortable with using the TS55, then the TSC 55 makes an obvious choice.
If you search the fog for TSC 55 you will find a few previous discussions about the saw. also if you search you tube for Festool Phil in the UK, he has made a good video showing how well the dust extraction using the supplied dust bag works with the saw.
I think a lot of people have a problem getting their head around the fact that the saw uses a dust bag, it's like going back in time. Well it's very clever how the saw works because that dust bag collects almost all the dust, there really is not a lot of saw dust on the ground when I have finished.
The dust bag does fill up quite quickly but is quick to change or empty and if you are going to use it all day like I have, you are going to need 4, 18v batteries and a couple of chargers to hand.
If you only work in a workshop then the TSC 55 makes no sense at all but if you work out on site and are on the move then it makes lots of sense.
If for some reason I had to hand back all my Festools tomorrow but I could only keep one, then the TSC 55 is the one I would keep. I could make do with my old drills, sanders and router but no other saw I have owned has ever come close to this one?
I hope that helps you, with seeing some of the benefits.
