Had one. Had to shim out the chain depth stop to take the slop out of it to make the tooth-set repeatable.
Lasted about a year, did "ok", and then the cheezy little micro switch went bad.
"Hello? HF? My switch went bad. How much for a new one?"
"Sorry, sir, but we don't sell just the switch. You have to buy the whole circuit board which is $45.95 plus shipping and will take about 2 months on special order."
"Thanks, anyway."
And into the dumpster it went.
Then I bought a Tecomec grinder from Madsens who I also buy my chain from. $230, but it is phenominally better, and opened up the option for variable compound grind angles to match the chains to the wood I'm cutting. Softer woods get a more acute set of angles while cutting the eastern hardwood that is the bulk of both my turning and burning is set to leave a bit more meat behind the beak for better durability. Also the chain depth stop and clamp are within 1/1000th when switching sides on the chain so the chain runs laser straight with no pulling or wandering in the cut.