Ask any doctor and he will tell you that treadmills are not great for your body. Jogging outside or on a treadmill will cause impact to your feet, legs and joints and over time it can cause serious damage. Elliptical machines are the far superior alternative to jogging as you get the same aerobic workout without all the impact.
Health clubs have started to make the switch from treadmills to ellipticals as many of them now have about the same number of each machine. A good elliptical machine will give you much the same workout as running on a treadmill but with much less stress on the legs. Elliptical machines give you an aerobic workout with a smooth gliding motion instead of the pounding you get while running.
It is unfortunate that elliptical machines are quite expensive and they can cost anywhere between about $1000 and $5000. When you get on one of the more expensive models though, it is clear they are of high quality and will most likely last for many years without breaking down.
If you want to go out and buy an elliptical machine for your home, you should do some research first. It is true that if you go to a store that sells the machines, they all look great lined up and brand new. It seems they should all perform perfectly just by the look of them. If you do your homework though and look up some elliptical machine reviews online, you will find there is sometimes a big difference between machines.
When you give the different machines a test by getting on them, you will immediately feel a difference between the more expensive models and the cheaper ones. Machines that cost only around $1000 to $2000 will feel much less stable beneath you and the circular motion will not feel quite as smooth. It is much like the difference you feel when riding in a cheap care versus an expensive one. The more expensive elliptical models will all feel very heavy and stable beneath you and give you confidence that they will not break down.
Another difference between the models is the bells and whistles. More expensive models may have all sorts of programs that will time your workouts and change machine speeds and resistance automatically during your workout. Only you can determine if that is something you want to spend extra for. In the end you should buy the machine you feel the most comfortable with that is within your budget.