Using the elliptical machine gives my joints the rest they need from the daily pounding from running.  I hook up my iPod to my ears and go.  Plus with the multiple styles of workouts available I can concentrate on the type of workout I need that day.  You can focus on the upperbody, or lowerbody as you need it.  With a treadmill you can only run or walk.  I enjoy being able to mix the elliptical and treadmill workout, but when my knees are bothering me, I can always exercise on the elliptical without pain.  Both have their pros, but I can't find any… read full review »