i work now around 3 weeks and more with the sinner ,i can say its well build and have a different hit and feel as the other rotarys i have use . And i have try a lot and all great brands. The running very fast and i notice the skin have very less trauma. Great healing . I can use carts when i need and have not to make any extra setup like to remove the spring. Its adjustbale from stroke ,very less to zero vibration and a nice weight with a good balance. I have line with a 14rl easy as with a sidewinder -a bit slower but with very less skin trauma. The Machine runs from 3.5v to 11v with a wide powerrange.