I had a co-worker try it and had success (50 lbs) but wasn't able to keep doing it for financial reasons. She said it was VERY expensive. Had to pay the $7 weekly fee all at once (so for example if they think it will take you 40 weeks to reach your goal weight, then you pay $7 x 40 just to get started). Then the supplements and vitamins were extra. If you don't reach your goal weight in time, it's the $7/week they pay, but you still have to do the supplements/vitamins.
Look into Sough Beach. It's a $10-12 book and is an easy way to eat a LOT of food, even casual dining restaurants. It's definitely worth trying that first than Slim 4 Life.
Good Luck,
J.