I joined last week having chatted to colleagues about it, and thinking it sounded like a relatively simple way to lose wait. I paid for the three month bronze package.
I have used WW in the past and in comparison I found SW a faff. I realised straight away that it wasn't going to suit me (I like to be able to join in with eating socially without having to consider combinations / 'syns' and whatever). You do need to weigh and measure syns so that's out for me. I tried it for a day, didn't get on with it and requested my money back under the distance selling cooling-off period. Then I checked the Ts&Cs and realised I couldn't. Stupid not to have looked into this properly in the first place, but I thought I knew what it entailed.
Basically if you've built your profile - which happens before you pay, at the registration stage, you're deemed to have started using the service, and so you're not entitled to a refund 
.
Pretty pissed off to have wasted so much money. All I can get back is meeting vouchers which are no good to me because there is only one a week locally that I can't do as I have a prior commitment, and anyway I don't want to follow the plan.
Just be aware of what you're signing up to, as far as possible with the life's information available until you've actually paid!