I purchased two Toyo Pistol Grip cutters and one had the TC600 head and the other had TC1. Both were used about the same amount of time. I found the TC600 head better to be able to score the glass more easily as the TC1 tended to skip at points. Finally the TC1 is no longer usable whereas the TC-600 is still going and now have bought a replacement head for the TC1. Seems to work as well as my other TC-600 and only time will tell if it lasts.