I have an elliptical trainer. They're adjustable to different levels of difficulty, so you could probably get as good a workout as you're willing to work for. Personally, I find I'm much more inspired by Cathe than by my own conscience and work much harder with the videos. I do the ET when I'm really, really tired but don't want to give up my workout completely. Also, while they're less impact on the knees, I find that they twist my knees a bit. Sometimes my right knee pops out of place briefly after I use it. It isn't painful, and it does it at other times as well, but especially after using the ET. If you have knee problems at all, I'd advise trying one out for the length of a full workout before buying one.