Ive followed both plans, I lost 3st with SW 2 years ago (I then re-gained my weight through pregnancy). I considered going back to the plan but couldnt find the motivation I needed. Money was also a factor. I enjoyed my time following SW but that was when I only had 1 child and I had more time on my hands to plan/prepare/cook meals. I was also financially slightly better off.
Ive chosen weight watchers this time round for a couple of factors... convienance/simplicity and money. I can eat anything I want following WW propoints and can easily follow the plan from home. I love the fact that you can buy WW products with the points values on - makes it so simple, also most the major supermarkets show point values on their healthier foods ranges. Lots of offers going on too. I also like the fact that the new proppoints plan allows you to have most fruit/veg 'free' (In moderation it seems) and if you fancy a tipple or a meal out you can easily stiick to plan without feeling guilty or that youve blown things.
Ive been following WW since 2nd January (new years resolution) and ive lost just over 1st so far... its been eay and I havent felt deprived unlike on SW. I used to weigh in with SW on a Weds night and have a blow out afterwards (Cause of feeling deprived) then I would do the same on the weekend but in reality I ended up cutting back again to try get my loss in before the next WI. It promted me to start having a negative view of eating.
So far I have my healthy foods, I have my treats, ive started exercising (1st time ever) and can have a tipple should I fancy it. Im planning a lovely meal out this weekend and its all within my limits and I actually feel like I still have a life.