The Lone Peak is the shoe that made Altra's name on trail, and the 9 keeps what people buy it for: a wide toe box for feet that swell over long days, a zero drop platform 25 mm tall, and a MaxTrac outsole that copes with most ground short of wet rock slabs.
It suits trail running, long days out and thru-hiking in roughly equal measure. At 316 g it is not light, but the ground feel and the room up front are why ultra runners keep coming back to it.
It is not a cushioned shoe. Twenty-five millimetres under a level platform is not much protection when you are twelve hours in, and the upper wears out faster than the outsole on rough ground.