I did this cleanse last year... the first two or three days are complete and utter hell, you suffer from "good food" withdrawal. I had a hamburger dream where I was eating a hamburger and it was soooo good and then I woke up and my hands were still in the shape of holding a burger, but there was no burger there.
My wife and I did it at the same time, I lost 10 pounds (in 12 freakin' days) and she lost 0 pounds. So not only could I not eat pizza, but my wife pretty much hated me because of the weight loss too.
Anyways I finished it without cheating and after the initial period where I wanted to eat everything bad for me, I got over it and my lifestyle didn't change to much.
The problem was I went back to eating the way I used to immediately afterwards and this cleanse should be more of a lifestyle adjustment. So hey if you're approaching it that you want to change your diet/life then all the power to you.. if you're just doing it to see if you can do it, I wouldn't bother.
Ps. I gained the 10 pounds back rather quickly.