Speaking from experience, I have never succeeded with Weightwatchers. I lost 3 stone a couple of years ago on a web-based basic calorie counting diet - but my weight loss stalled (still had another stone to lose), then put a stone back on and after several false starts over the last few months have realised it just isn't working.
Joined Slimming World 3 weeks ago...and have lost an average of 2lb a week You can eat loads, it has really forced me to eat more fruit than I ever thought possible and really sorted out my bowel issues (tmi ) The downside is that you have to prepare all your food (no ready-meals) and think in advance as you can't just pop into a shop and buy a sandwich for lunch (limited amount of bread allowed) but best diet I have done
WW - basically you can eat what you want as long as you don't go above your daily points total (every food has a 'points' value) so you need to watch your portion sizes/measure everything.
SW - you can eat as much fresh fruit/veg, pasta, potatos, rice, beans (including baked beans), lean meat and fish (any sort), eggs and fat-free yoghurt as you want - no need to measure portions. You get a couple of extra things a day (one calcium-based and one fibre-based) plus between 5-15 syns each day to use on whatever you want (I have worked out that a 'syn' is worth about 20 calories).
Depends on what suits you - I love to eat so not needing to worry about portion size is fantastic for me. If I go out for dinner now, I don't have to worry about what is the lowest-calorie item on the menu but can have a steak, jacket potato and salad and don't need to worry about how big the steak and potato are as I can eat it all
Pretty yes - pretty much every other foodstuf other than those I have mentioned are restricted...you can have (wholemeal) bread as your fibre healthy extra but everything else such as cakes, biscuits etc can be eaten but you do need to use your syns for them.
The post that Furball has linked to explains the red and green days but there is also the orange days now where you can combine the 2 and eat all the carbs and proteins together.