Tony Little's Gazelle is like an elliptical, except elliptical machines don't have small muscley dudes with big ponytails advocating on their behalf. And most ellipticals don't lead to uncomfortable moments of possible sexual harassment.
Elliptical machines also offer resistance, which some models of the Gazelle don't have; you're basically just swinging your limbs back and forth until you get tired. The Gazelle claims to be a full-body workout, and while your legs, butt, and arms are moving, the Gazelle is more of a cardio workout than muscle-building machine. At more than a hundred bucks a pop, you're better off sticking to the equipment at the gym.