I have a ski buddy that has one that sits out side his office in the warehouse, he has had it for over 5 years, its been collecting dust as he has went to riding his bicycle to work. I have used it several time, it does give you a workout, its basically a slide mechanism connected to some very large rubber bands. I would think you would get the same or better ski workout with a trikke
http://www.trikke.combrad