Slimfy, from my experience, is a non-starter for the serious dieter.
I never lost more than 1 kg, probably that part of my brain that was missing when I bought yet another "let's have your money" product!
They answered one or two e-mails, except when I told them that their product does not work as advertised. No comment?
At the end of the day, it is back to calorie counting and exercise.
Bottom Line: No, I would not recommend this to a friend