You don't need to do a low-carb diet when you have an endocrine disorder like PCOS. I don't have it, I have a remarkably similar disorder with things added on top. I'm not doing low-carb: Atkins made me very sick. I would say that there are definite similarities in my diet to South Beach, because I try hard to get the "good carbs", from fresh fruit, wheat bread, etc. You can buy pasta made out of whole wheat. I eat potatoes, just not a lot of them, and I eat white rice. Brown rice does strange things to my already sensitive digestive system. But basically, I count calories and watch what I eat, and exercise. The exercise is important even if you don't lose weight while doing it (I sure don't: I spend 2 hours average at the gym daily), however I also don't have any of the associated disorders that doctors seem to think come from being overweight: asthma, high blood pressure, sleep apnea, etc.
There are people here in this part of the forum following all kinds of diets. Some are doing Atkins or South Beach, others are doing low-calorie, low fat, and others are doing things like Body for Life.