Sounds like the guys that run the stihls need to not get so crazy with the rakers and keep the bar nuts tight. I've got a 660 that has at least 4 million feet of timber on it and I've never put a tensioner in it. No doubt the 395s run really well, but, they are the closet thing to a railroad tie with an engine as a handle you'll find. I ran one for two years alternating between that and my 660, what the 660 gives up in power it gets back in fuel mileage and user friendliness. O yea, you don't have to carry around a pocket full of bolts either when you run a stihl.