I did ww a few years ago. It did work for me but I always felt like I was "on diet", I had to be hungry in order for the diet to work. I did not like the points counting system (admittedly I have not tried their new systems which I don't know at all), and their meeting was preachy, and clicky. I felt reprimanded at every meeting, my losses were never congratulated, my consultant barely knew my name after months, and I felt excluded by the popular in crowd.
I have the opposite experience at SW - I don't feel like I am on diet, I enjoy this way of eating as a lifestyle, I am never hungry, I don't have to count points or weigh food, my consultant and group are lovely and I learn stuff at group rather than feel lectured at, and it works too.
The group thing is due mainly to the personalities of the consultants I think, and I guess that is just luck, but the points counting and hunger thing...... much better at SW