I have used them before and they definitely do work but only as part of an overall regime. They are good for toning and strengthening muscle, which in turn can boost metabolism longer term. It is no replacement for calorie-burning workouts though; if you fancy giving them a go I would recommend them alongside walking/running/spinning/zumba etc etc. I would hold back on purchasing one though ( unless you have money to burn!) and try them out in a studio or gym first of all. Be careful of where you go though; I have seen salons that simply allow you on the machine for 10 minutes and provide no instruction or supervision whatsoever. Some people think you simply have to stand on them for 10 minutes and the fat will miraculously fall off you. Sadly this is not the case! You need to be doing the exact same exercises you would do in a floor/ free weights session - planks, squats, lunges, tricep dips, etc etc except on the plate. Make sure you go somewhere that will work with you and provide instruction as to how to get the best out of them; anything else is borderline dangerous if you ask me