I have only sharpened 5 or 6 chains so far but it seems to work very well. A couple of the chains had some damaged cutter so it was much easier to get them into shape versus hand filing. For touch ups filing is the way to go but when you need to remove greater amounts of metal the 410-120 works great. A lot of online reviews stated that the aluminum oxide grinding wheels are garbage. So far they are working well for me. If I was doing this professionally I would probably want to get the CBN wheels. When these standard wheels do wear out I’ll probably upgrade but why trash something that’s doing a decent job, just need to go slow.