Sure have. I am following the Dukan Diet and have lost about 25 pounds. I have been really sick the past few days and have gone off the diet, but plan on jumping right back as soon as the doc says it is OK.
I plan on reaching my goal weight by the Canadian Thanksgiving, which is the 2nd Monday in October.
I love SP as there are different tools to use, teams to join (including a Dukan Diet one) and great support thru SparkFriends. My friends have helped me thru lots, as I have helped them.
Hope you have success in your journey.