HCG diet...anyone heard of it?

Ive been reading a lot about it and would like to find someone who has lost weight...and kept it off. From what Ive been reading about this diet is that it has a VERY good sucess rate, and hardly any side effects. But, I am weary about the restrictive 500 calorie diet part of it, and whether or not the weight will stay off after the diet is over. So can anyone give me any information? And, do people typically lose alot of weight on this diet? It seems to me that most people do, but I want to see what people say on here. Im 5'6'' and weight about 250lbs...so I have a considerable amount of weight to lose. Sooo any help or insight would be appreciated