My advice like many others is do something that fits into your lifestyle. The biggest failure of any diet is not being able to stay on the diet.
Most trainers will tell you eat anything you want in moderation-most people can live with that. I dont know many on weight watchers, but my pop was on it, and stayed slim by doing it. I think its hard to keep weight off unless you learn to reduce the amount of food you eat and exercise-every Dr and nutritionist will agree to that statement. So think of the rest of your life and say, will I be able to eat low carb for life? Do I really want to? Big questions that you should sleep on and decide.