Montignac is not that low carb, but is more low carb than a "normal" diet. Montignac focuses more on low GI food but also talks about "protein meals" (as the egg&bacon breakfast). I have ordered (but not received) Atkins for Life, and from my impression his maintenance diet is very much low GI. I think it's really healthy food.

I think that Montignac/Somersizing and other low GI diets are for slower weight loss than a jump start on Aktins. OTH - you get your daily menu correct form the start and can maintain almost the same diet for the rest of the life. With a real low carb diet (like Atkins) I think lots of us slowly convert towards another diet - and it can be hard starting to eat low fat cheese once you have gotten used to those really fat and creamy things (for example).