yes, I went on it last year for a bit, probably about 2 months or so. I didnt really stick to it religiously, I went out about twice a week and drank a lot, and often had treats but I lost about 10lbs altogether. I didnt go to the groups, my mum went and I just looked through the book and followed it.
Basically there are two 'days' you can do - a red day is when you eat mostly meat and fish (unlimited quantities), with a little bit of carbohydrates, and green days are the opposite. I preferred green days, you can have unlimited amounts of potatoes, pasta, baked beans, eggs etc. There are also 'free' foods that you can have unlimited amounts of on both days, these are fruits, veg, coffee, tea, diet soft drinks. You have 2 or 3 healthy extra options each day, things like bread, cheese, milk, cereal etc, it tells you how much you can have of each thing. You can also have treats, they are called syns, and things like crisps, chocs, alcohol etc have a syns value that you can have aswell as your free food and healthy extras. you can have up to about 15 syns per day, (I used to have about 10) e.g. a dairy milk bar is about 12/13 syns.
It sounds kinda complicated but once you get going its easy and you think it wouldnt work but it really does. Obviously you have to have loads of water + fruit + veg aswell, and exercise helps. its really easy to stick to, for e.g. on a school day I used to have cereal for breakfast (1 healthy extra), with some fruit, at morning break I had some fruit or a muller light yoghurt (free) and for lunch I had sandwiches (healthy extra) with tuna, dairylea or ham and a pack of french fries. For dinner I would have something like a jacket potato with beans (free) or salad. there are some nice recipes in the book aswell, like egg and chips.
hope that helps and good luck!