Nice & Informative post.
In my experience, these kinds of schemes are always Ponzi. Never ever invest your money in such schemes however legit they seem. It is never realistic to expect an earning of 3-4% daily interest on your money.
Just a few lucky ones, who enter early into such schemes are able to get their money back or sometimes earn some profit too. But, in my opinion, those early birds are the people who spread the news of such schemes to others because of referral bonuses. So, in essence, these early birds just provide the shoulders for these scheme builders to put their gun on and kill the money of the referred ones :D
Just an observation....