I have found personally that my willpower is much stronger while in ketosis. Now that doesn't mean that I still don't have cravings for things....serving my children ice cream or cake the other night kinda pulled at me a bit, it looked and smelled great and sure, I would have liked to have some. But it was much, much easier to say no to it since I am in ketosis. Being in ketosis has also helped greatly with my urges to binge and with my mood regulation which is the main reason I started doing this in the first place. I am also able to focus better and am starting now to get some mental clarity, which is nice because I have been foggy from the carb flu.
Alternately, I find that even when eating a strict primal/paleo diet, I still have difficulty with mood regulation and binges, and my willpower is lacking. If I were still eating the traditional primal fare with sweet potatoes and other starches, I would be triggered to seek out more and more carbs and/or binge. So for me it seems (at least so far) that NK is the way for me to go, but I'm still very early into it. All I know is that every time I have been in ketosis, I have a greater sense of wellbeing and feel in control over the foods that I put into my body, instead of feeling like the food is controlling me.