When we were much younger, my brother and I lived together for a couple years. He had a male Doberman that he free fed, and I had a female GSD that was not. For his Dobe, my brother would just bring home 40# bags of dog food, open the top all the way across and roll down the sides a bit, and that was his dog's food bowl for the next month or so. My brother would periodically roll the edges down as the food disappeared and that was it! His dog was always very trim and well muscled, and never over ate.
My GSD, on the other hand, would eat until she popped if she had access to food...But she would not under any circumstances get into the food bag. I truly believe she would have starved herself to death, with the open bag of dog food right there, if no one put food into her bowl! On the flip side, if you put 12 cups of food into her bowl she wouldn't leave until she'd eaten every last kibble LOL! In her later years it was hard to keep her trim, so close regulation of her food was a must. I don't know if this was a genetic thing or a personality thing, but free feeding would have shortened her life for sure!
For me, especially considering the training value of food, I would never free feed a dog. But clearly it does work for some...
It's not the size of the dog in the fight, it's the size of the fight in the dog. Mark Twain