Diets like Medifast and NLD could easily result in a quick regain if you are not careful, because they are very low calorie and low carb. Instead of stopping suddenly, it's recommended that you transition by gradually adding real foods back into your diet. You'll still need to watch your calories, probably for the rest of your life. The diet never stops. It's maintenance
Nutrisystem would be about the same way, as are most diets. If you stop any diet plan, you risk regaining unless you very carefully monitor your calories.
Of the diets you listed, I would recommend Medifast first. I tried Nutrisystem and hated it, the quality of food was just horrible. However, some people do like it.
The NLD plan is very iffy, in my opinion. From what I've been told (and I've not verified it but it came from someone that researched this), it's just some guy that buys the mixes from a manufacturer that sells them in bulk to a lot of different places. There's not a medical team behind NLD to back it up. They get their products from Robard, who will do private labeling of their products for anyone. You can buy them from other online sources as well, often cheaper than NLD.
Medifast does cost more, but it's not the same product. There's a lot more research behind it, and you get support from a staff of nutritionists.
That's just my personal opinion