I did it for a while - more for the convenience than the weight loss. I didn't like the dinners very much. Yes it is expensive, but you only need to buy milk - everything else is supplied for 3 main & 3 snacks every day.

One of my mates at work did it for the weightloss (he needed to safely lose weight before brain surgery to deal with epilepsy). It worked for him.

Good luck with it.