I just (within the past two weeks) stopped Atlkins, so I'll give you my experience on it.
I started Atkins with a goal of losing 30 pounds. I started with the Induction phase and I kept accurate track of everything I ate during that time (I used FitDay online because it's free and it appears to be pretty accurate). During the first week I lost 10 pounds. I kept my carbs below the levels for Induction and I was getting the majority of my carbs from the vegetables, just like they advise for that stage. One thing I will add is I did suffer the "Atkin's flu" the first week. My legs and neck ached and I felt tired and gassed pretty easily during exercise. It only lasted about 5 days and it wasn't unbearable or anything, but I didn't feel good during that week...
The second week I lost absolutely 0 pounds and I had changed nothing. I'm analytical by nature, so I know beyond a shadow of a doubt that nothing had changed. I was consuming the same carbs/calories/fat that I did the first week and my exercise routine was identical to the previous week.
The third week was the same as the second. No weight loss at all. Same diet, same exercise. No results.
After the third week, I switched to a 'normal' diet. I ate standard amounts of carbs and just watched my overall calorie/fat intake and kept those down to diet portions. I've lost another 6 pounds since I switched (just over a week ago), but my exercise regimen fell off because I got a cold and just haven't felt like exercising. My big fear was that all of my weight loss would be water weight that I would gain back once I introduced carbs back into my diet, but so far that hasn't happened.
Overall, even though I had mixed results, I'd certainly recommend it. It does give you a different perspective on types of food and I am crediting it with jump starting my weight loss. I don't know that I would personally want it as a lifestyle, but there are probably a lot worse choices too.
Good luck with your weight loss, regardless of your choice!