Though I was never officially diagnosed I am sure I had pcos as I suffered from all hallmark symptoms (high testosterone levels exacerbated by insulin resistence).

After being on low carb for 10 months, I can share with you the following improvements, all of which I attribute to normalizing my testosterone and hormone levels from lowering my insulin production:

1) Moods have become stabilized, I don't feel as tempermental and aggressive as I did before. I also do not feel as prone to depression.
2) The excess hair growth has stopped forming a new, but the existing hair has thinned out considerably. My arms are no where near as hairy as they were before, the hair there is barely noticable now. Also when I wax or tweeze the excess hair which is still noticable (such as on the sides of face or under the chin), it grows in finer and slower than before.
3) The acne I suffered with my whole life cleared up almost entirely within a few days of starting LC. This amazed me. I now have flawless skin that never breaks out, even though I am still overweight.
4) The greasyness of my skin has decreased considerably.
5) Before I started low carb I never had periods. I now have them regularly every month. I also ovulate every month.

So there you have it folks. LC pretty much drastically improved or totally reversed all of my PCOS symptoms. Of course, if I overdo it with high GI carbs (such as maltodextrin abuse i.e. eating too much splenda), all my symptoms return. But sticking faithfully to controlled carb has helped me keep the insulin and other hormones in check.

My only complaint is the hair on my head is still thin, and has still been falling out a lot. However, I attribute this hairloss to weight loss induced stress, and I assume it will stop (and grow in a little thicker) once weight loss is stopped. I was born with very thick hair, however due to the PCOS my hair is now on the thinner end of average. I am hopeful that in maintenence it will grow back in a little thicker, although because many of the hair folicles were killed by the high extra testosterone I am not expecting my natural thickness back.