Hi Suzanne.  I have a Precor EFX Elliptical trainer.  I love it!  It delivers a great intense low impact workout.  The first few times I did it, I didn't think I would get as good of a workout as I do when I do my treadmill.  But, I must say, I was sweating just as much and my heart rate was just as high.  I usually set the resistance on "7" and vary the incline.  I do love it, but for some reason, I don't use it very often.  I always go back to the treadmill, and Cathe cardio. But when I need less impact, I get on the elliptical trainer! Another plus is that it is soooo quiet!  
Linda