I have a mini stepper and when I used to use it I never had a problem. I actually lost a few pounds and inches both. I only did like 20 minutes 5 days a week with great results. Helped me tone up the butt and hips. Then I stopped and of course got dumpy again.
I used to use the elliptical too. No results there but I think I was eating wrong.
I think they are both great machines. Of course the mini stepper is a lot cheaper. Mine was 40.