Worked for me!
I started the Zone about seven years ago after I had gotten way, way overweight. I liked it because it did allow me to eat things I liked, which were mostly healthy anyway, but forced me to limit myself on the things I shouldn't be eating.
Because I felt so unrestricted but guided, I was able to work up some really good meals that weren't missing much, and if I did cheat, I never felt like I'd blown the whole diet.
I ate a lot of chicken, which I do anyway, veggies, usually a little bread (like a small dinner roll) and a little fat for flavor.
I lost 65 lbs in six months and kept it off for years.
When I would go off the diet, I would gain, but I could go right back on and take it off. Granted, I did religiously work out, which added to the weight loss and muscle gain, so I honestly don't know if just going on a good diet of balanced meals would have done the same.
I felt a LOT better, I mean a lot, like 'new person' better and because I did have guidelines, it helped me. I know people who need a meal plan to stick to, and not just a general eat good plan.
It worked for me because it gave me guidance and made me look at my food. It taught me to make good choices, and after doing it for a long time, I was able to eyeball a lot of things and keep with the diet even when not at home.
I also found the website fitday useful for tracking.
Note: See the Fitday Software Suzette Kroll, RD recommends.