I did South Beach to lose ~20-25 lbs after college and have maintained my weightloss over the past three-four years just by the habits I gained from the diet. I have the last ~8lb to lose though and I've never been this low of a weight in my life other than a time when I wasn't eating and doing shift work. The reason I'm not lower is just because I have been drinking more than I should and eating "crap" on the weekends.
The first two weeks are the only time when you're really restricted on bread, pasta, rice, etc. The rest (phase 2, 3 and "maintenance") all include them. I'm a rice/pasta/bread JUNKIE and it works for me. Now I have retained a lot of the habits I learned on it, and it's much easier to maintain my weight (eating oatmeal w/ flax seed, only whole grains, lots of veggies, lean meats, etc).
Everyone is different and some people love the south beach diet, others hate it, and many others just don't understand it. Take the book out of your library or read up on the official site to learn more about it. If you just think you need to cut out carbs, it's definitely not SB. The weak feeling many people complain about is your body going into ketosis, and that is NOT the goal on SB, and can be avoided with the right mix of veggies, dairy and legumes.