No one can make a guarantee FACT. Any business making a guaranteed statement as asking for trouble. I was thinking to do business here and see how things roll. However after seeing a guaranteed statement think am going to stay well away from this unless someone wants to guarantee an escrow service if does not pay will pay me instead.
As for me, I never invest more than I can lose. All investments have risks, even bank investments. But the the ratio of profit and risk are always different. Here this ratio is the best.
I can make a guarantee and I do. However, there are still some reasons of losing money remaining: Bitcoin will be banned by the authorities, doomsday, etc.
I just said that the business model of the site does not suppose that the site will be closed with time, regardless of other users activity and investments.
If you invest, you will say me "Thank you" after time.