I use the Stihl USG (bench mounted). I really like it, but like said before if its done wrong it will over heat the chain and cause it not to hold an edge or make it hard to file by hand. But we sharpen chains here since we are a Stihl dealer so its nothing for me to go sit at the sharpener and sharpen 10 to 30 chains a week. So Ive got plenty of practise with it. The big thing is dont try to take it all off at one time, you got to take a little off at a time and go around the chain a few times so it dont get too hot. So my advice if anybody gets a sharpener like this is to start with older chains first in case you burn it up.