There is only one tried and tested method to lose weight and which works for ever.It involves 2 steps:
1)Diet Modulation:NOT Diet.because u cannot diet for ever.So in case you are overweight,you need to exercise and diet aggresively.
Once you are down to the desired level,both should be toned down,just enough to maintain your weight at the same level.
2)Exercise:Lesser weights,more of aerobics....walking/joggin is the best along with crunches and side bends for the waist line!
About all these devices,I have often seen that patients who have a severe fracture of the jaw and have to be put on INter-Maxillary ligature lose weight in the same duration as they are mainly on fluids.
But the moment the wires are off,they not only regain what they have lost but also add a few more.
Sorry but I really do not believe in all such stunts!
P.s.Its a free world!