I agree with you, WereBear, that the carb ladder is one of the things that makes Atkins superior to SBD - it allows you to slowly tentatively try new foods and figure out which ones work for you personally. And it allows/encourages you to back DOWN the ladder if need be.

One's success on SBD long-term probably has to do with the degree of insulin resistance, and how much of those higher carb foods you try to eat. I never got the impression that everyone would be able to increase their carbs significantly. I learned quickly that grains and legumes were not a good fit for me; giving up starchy veggies was never a problem. Agatson suggests that one gradually tries increasing carbs "till one stops losing" but he unfortunately doesn't include the support of the carb ladder with its tested sequence of how to add carbs (though that sequence does seem to change with each major rewrite of Atkins).

Anyway, I think we are all in agreement: South Beach is a good intro to Low Carb and Atkins is the Gold Standard.