I use both at the gym, too. I find the elliptical to be as good a workout if you work at it. The problem is is that the treadmill is set at a specific speed so you keep up without thinking, the elliptical is not set so you have to consciencously keep up your speed. When I do work hard on it I get my heartrate up as high as on the treadmill. I also use it on an incline for parts of my workout - that gets your heartrate up! Good luck with your shopping.