I went, (and could do with going back after having 2 children!) it worked well for me, weight loss is fast and stayed off for a good amount of time. Basic theory is don't mix your protein (mainly meat) with your carbohydrates. Good diet if you like eating!
I Go, been going nearly 3 years since i had my little girl. The Diet does work, the reason i chose slimming world is that you can fill up on free food all day and as much as you like where as other slimming classes you get so many points and once you have had them thats it till the next day. I also went before i had my liitle girl and lost 1stone 7lbs in 3 months, having put 2 stone on when i had my daughter i have lost 1 stone 6lbs.