the biggest loser? anyone tried?

Has anyone tried this diet? I seen the shakes and stuff in tescos and I then went on the website and it looks pretty decent? Theres a thing going on the UK website right now not sure if its the same in USA but if you don't lose 1 stone in 6 weeks they give you you're money back, ive read all the small print and they actually do! Theres 3 options, meal replacement, calorie controlled diet or vegetarian diet. It's really tempting me!! Only £12.99 a month too....anyone done it?