Uusally, anything whose promotion relies heavily on testimonials is questionable. If it is a money-back guarantee, then no problem.
The reason that testimonials are a problem is that they are always limited to positive testimonials -you never see reports from folks who got no results or bad results. And if the testimonials occur in the context of advertising or self-promotion -as opposed to the findings and report of third parties- they are basically meaningless. That said, if the worse than can happen is nothing -and you can get your money back, then I say, "What the heck. Give it a shot."
Good luck.
68 dollars i paid 600 for for the linda set. but ti worked very well