I did one 12-day Master-Cleanse in August and then 4-days at the beginning of October. I'm thinking of doing another 10-day at some point.
The Master-Cleanse has really helped me change my eating habits, as it is much easier to do without dairy/wheat/sugar than it is to just drink lemonade! It changed my perspective a great deal. Instead of feeling like there's nothing to eat (without junk), I know there is tons to eat and enjoy.
I did have big Sugar cravings afterward, and food fantasies during. Maybe because of all the maple syrup? The first few days eating again I was tempted by all my food fantasies -- but after I got through that, things got much easier.
I also did colon cleansing and four liver flushes.