I bought this as a casual shoe. Recently, I began using it as a light trail running shoe. It's a real sleeper. I run on a rail trail that is essentially a long, seven mile uphill grade, and downhill on the way back. The regular Cloud works perfectly. It's low enough to the ground to get traction and speed uphill. With the fairly even heel-toe ratio, there's no heel pounding on the downhill. I've shaved a minute per mile off my trail run in the Cloud. All day everyday shoe, sure, but a real good time running, as well.