I do SW. It works for me. Different things work for different people. If we all had a healthy relationships with food we wouldn't need to 'diet'.
I am vegetarian and suffer from GERD so really can't do low carb, high fat, high protein - I have tried but I had acid/indigestion, headaches, tummy ache and bloating all the time. I can't do 5:2 as when I have very low calories i feel ill and light headed. I have done meal replacements, ok for a month or so to loose a stone but then you need to do something else. I have done WW but just prefer SW. Less counting. Some stuff being free, once you know what that is, you can grab stuff without looking/logging everything.
On SW I eat mostly fruit, vegetables, quorn, cottage cheese, yogurts (mullers, brooklea or other fat free or total greek 0%) with some carbs. I don't go mad with the carbs and eat less than I used to, bulking up with veg. Most days I have some cheese (30-40g), either cereal, bread or ryvitas and a small amount of chocolate/something sweet and some sauces/dressings/gravy to add flavour. I have milk in drinks (which I don't bother counting). I use frylight, don't have butter and try to only drink at weekends (I managed to do dry January). I have been making lots of soup :)
For me this is a healthy diet. I have stopped cooking with oil, and cream, mostly stopped eating processed food (I have an occasional ready meal or mugshot) and cut down the bread and booze. I eat much less chocolate, crisps, biscuits and cake but can still have them now and again. I am mostly not hungry and enjoy the food I am eating so am much less likely to eat junk.
I know what I need to do without going to SW but without that focus I get from attending group (and talking with other SW members) I struggle to stick to the plan. Once I stop going, I slowly drift back into bad habits.
It is not so much a case of when you stop the diet you put on weight but rather when you start eating crap again you put on weight.