As a fitness enthusiast I like to look at what new fitness equipment is available and what key benefits there are for using that equipment. Unfortunately much of the new fitness equipment sold today is either a re-make of an old device or a variation of a machine which in principal is great but in practise doesn't work. Take for instance exercise bikes with rowing action, these things have been around for years and in most cases the rowing action acts as a hindrance to cycling. Although you could argue that an exercise bike is safer and more convenient than buying a normal bike and going for a ride outside, I would still recommend that the traditional bike ride is much more beneficial to body and mind.

Occasionally I do see a product which is not just a fad device and there may be some benefit to buying one of the exercise machines over buying a new pair of trainers and getting out side. A device which has been around some time but I have only just realised the potential benefits of having one, is the lateral thigh trainer.
As a runner I do plan my training and ensure that my training targets particular body systems, for instance, endurance, stamina, strength or speed. The lateral thigh trainer is ideal as a substitute for strength work. Normally I find a hill and run up and down a few times but this causes a huge impact on the knees on the way down, with a lateral thigh trainer you can exercise all the same muscles in a high intensity workout similar to doing hill work but without the risk of knee injury.
If you get a trainer with adjustable resistance like the lateral thigh trainers here then you can vary you training plan to have short high intensity or longer mid intensity workouts.
If you are not a runner but you are just looking for an alternative exercise, other than actually putting on some trainers and going outside, then the lateral thigh trainer is good for aerobic exercise as it provides a low impact exercise which uses muscle from the whole body.
I can highly recommend the lateral thigh stepper as an exercise device either to supplement other training or act as the main exercise in your lifestyle.