I have seen people lose weight and keep it off on other types of eating plans (weight watchers, etc. or just generally low fat).

Not everything works for everyone, and I would never want to push LC on anyone (having been on the other side where someone was pushing low fat onto me). However, if people are interested I am sure to take the time to educate them on what I actually eat on low carb. People are usually quite suprised my diet is as balanced as it is.

I generally eat meat, eggs, cheese, and veggies with few to no LC "convenience" or "snack" foods. I dont feel I need them b/c I am satisfied with what I am eating. Low fat never worked for me because I was always hungry and then would eat a box of low fat cookies with the rationalization that they were low fat so they must be "healthy" or at least not bad for me.
I couldnt understand why I was gaining weight.

I am full and satisfied easier and for longer on LC so I dont really snack, and when I do it isnt something loaded with sugar.

My point is, many "diets" or eating plans will probably work. But not everything works for everyone, and generally the diet (or whatever) has to be balanced to work at all. I dont think I'm missing anything from not eating bread or sugar that my vitamins dont give me and I have certainly gained alot health-wise by eating the LC way!