We test ran one from the shop for a day.
It was impressive. We had a line of 25 pine stumps average of 18". It chewed them in about 4-5 sweeps a peice. Couldn't bog it down. Controls also felt nicer than my old unit.
My friend had one catch on fire on a job site. Had 600 hrs on it. Hot lead cable from battery chaffed and ignited.
They have a ton of power but any part you need for it will cost a ton.