This is definetly a scam. It is like btcbum. Both games a reso cool so it is a pity but the amount of interest they pay you is insane it cannot be sustainable if they give you back over 2x your investment in less then 250 days.
Even the free investment you get gives you 25 satoshi per hour without doing anything that is like $1,50 a month. I do not see how the site owner can afford that. If it was a faucet and users went online hourly then I can see that earning making sense but other then that no, not really.