It works for me. You don't just eat the NS foods, you have to add in your own fruits/veggies and dairy/protein.
Some foods are good, some aren't. They just reformulated a lot of their foods (mostly for the better). It's really a matter of taste, and I think your taste buds get used to it as well. NS formulates their foods to be low to moderate GI - which will end up keeping your fuller for longer. It teaches you portion control and what balanced meals are.
I have been changing over to every other day eating my own foods, based on the NS guidelines (kind of like the Zone).
The $300 may seem expensive - but you get food, and a meal plan to follow, free access to nutritionists, dieticians and counselors. So it's up to you whether or not you get your money's worth. And if the program isn't for you - there isn't anything wrong with that either!