Does an elliptical/cross-trainer work for better weight control and stamina than a treadmill?

If the intensity is the same on both machines, then the elliptical machine is much better. The reason is because you're using more muscles during the exercise, as long as you make sure to use the arm movement when you're doing the elliptical.

The more major muscle groups you use doing an exercise, the more overall calories you will burn during the session. This is the reason why cross country skiing, swimming and jumping rope are such great exercises. The calories you burn during these all body movements is staggering.

I get a better workout off the treadmill, but the elliptical trainer doesn't hurt my knees or feet as much as the prior. Try the rowing machine too, that one really makes me sweat.

It's a toss-up. Ellipticals are supposed to be easier on your joints, but I don't like them because you can't adjust them to get a comfortable "stride." In terms of calories and fat burned, however, they'are about the same.