Worth investing in to companies like hashflare.io or genesis-mining.com?
Hashflare:
During black friday there's discount - 1TH/s for 100$. Maintenance fee for 1 TH/s is 0.4$ == 0.0005 BTC.
1 TH/s gives 85-90000 satoshi - 50000 satoshi MEF = 35000 satoshi profit (0.257809$) * 30 = 7.71$ per month, 7.71*13 ~ 100$. So, ROI is 13 months...
But profit for 1 TH/s would vary during a year. So 90000 satoshi per 1 TH/s might be even lower, right?