Yeah ofcourse! Im glad you asked first before using their service because i feel like it IS a scam...

They do give back double your coins (well they did up until this point...i cant look into the future) but not in the time they say (57 days). When I began using their service in february they gave me about 1/29th of my "investment" each day so that was awesome but since april they have been screwing people over in my opinion.

Since april they send around 1/1000th each day which means my investment will be doubled in 2000 days and they keep on misleading people by still sending 1/29th to their own accounts so it looks like they are still a good service to use.

So in conclusion... if you want to wait 2000 days on your investment to double (which isnt even sure, they could stop paying out any time) go ahead and use their service but I dont think its worth the wait, its more efficient to just power up the steem and gain more that way

Hope this helps :)