I use Eobot and i will say that its not a ponzi but its not profitable too. I have not invested any money in this but i does pays you. It depends on the mining speed on how well and fast we get our coins. If the speed is good then we will mine coins faster and will be able to withdraw them faster too. Cloud mining should not be treated as a source of income . Eobot says it on their website " Cloud mining should be considered as a fun, recreational activity and not a source of income or investment " and this shows that its a genuine website.