I have no knowledge of Cambridge Diet to compare to but one thing that Slimming World isn't it strict. Minimal rules, minimal weighing, minimal counting. Lots of "free" foods to fill you up and nothing really is prohibited.
I am already on Cambridge, but after I go into the maintenance I want to try something else. I think I will go and do that one, the variety and healthy options seems very appealing!
I am no expert but I 'think' after doing CD you have to stick to low carb or the weight will just pile on, dont quote me on that though! and with SW you can eat lots of carbs I think (best ask Ian )
sorry for the thread hijack but just thought I'd mention it.
Slimming World allows for lots of carbs if you want it... (particularly on the green and extra easy plans). On red days however - potatoes, pasta, etc, are strictly controlled as Healthy Extras.