Have many servos, several brands, over nearly 25 years, yes they work, but most have developed some slop within a couple years. Can't be positive, but my first really good ones, KO FET servos in my Vintage rides, sure don't seem nearly as fast as they used to be. New gear set would likely help the slop, but I think it would take a comm cut and new brushes to get the response back. Don't think they will fit in my lathe though! Also all in electrics.