I've been obese all my life and have tried every diet there is pretty much, including SLimming World and I've seen and heard success stories on all of them.
For me, Slimming world didn't work because it was too easy to over eat on carbs which were my main downfall in the first place. I never felt full despite mountains of food and it was too easy to "save" all of my syns up until one night when I'd have an almighty binge (binge eating is also an issue for me).
I also found the amount of fruit/ sugar I could consume consequence free was alarming. 2 muller light yogs in a day plus a couple of pieces of fruit and you're knocking on for 8 teaspoons of sugar. That's a massive amount of sugar that pushes up your blood sugar, only then to crash and make you hungry again a couple of hours later.
I found I was eating breakfast (overnight oats) at 9, then needed to snack on fruit at 11, have lunch (usually soup and a sandwich with my b option and ham/ tuna) at 1, need a snack of a yoghurt or fruit at 3, then have dinner when I got home at 6:30pm. That was all perfectly reasonable on slimming world, no cause for alarm that I was getting hungry every 2 hours! 
I lost 4lbs in my first week, then steadily gained those 4 back in the next few weeks despite sticking to the plan. I was told at group that I was lying and MUST be "cheating" 
The group I was in perpetuated the idea of cheating and "falling off the wagon" which I hated because I really wanted to believe it was a change for life and sustainable, not just a temporary diet. "I've been good this week" or "I've been bad this week" was a common theme...
That's not just SW by the way, I also went to WW meetings and it was the same there.
ANyway long story short, a life time of high carb, low low fat diets left me at 19st 1lb at 5ft 5 and 26 years old
... that was on new years day this year.
Thankfully, a month and a bit later I found LCHF on here over on the bootcamp threads and I haven't looked back. I've lost 3st 5lbs on LCHF and a further 10lbs before that just by giving up low fat products and introducing fat back into my diet.
I'm 15st 10lbs now and losing about 2lbs a week by eating proper food, no low fat products at all and plent of good fats and low carb veggies :) Never enjoyed food more to be honest and I can now eat 2 or 3 meals a day and not be hungry at all.
So yeah, you have to find something that works for you and not be afraid to try different things. My issue was metabolic syndrome - I was struggling to keep my blood sugar stable and therefore felt hungry and craved sugar constantly. As soon as I broke that cycle LCHF became the easiest way to eat I've ever found 
However, if your problem is something different then something else will probably work for you in the same way :)
Good luck :)