Does an elliptical machine or a standard treadmill provide a safer exercise option?

An elliptical machine is good for bad knees (Its like a cross trainer) as they don't land any pressure on your knees. On the other hand treadmill will force you to put your leg on it again and again which can cause you pain. So my advice is to buy an elliptical machine. For more information go to:- http://www.ellipticalvstreadmill.us/