this surely is scam, noen of respected blogs review this
PBmining have been paying its customer more then a year... So I don't think so..
There are reviews on the blogs!
But paying out more than a year doesn't mean they are really mining! 
~~MZ~~
That's true for sure, but I think most people aren't interested in whether they are mining or not.
They just want their weekly payouts. As with all investments, there is always a risk. Risk is something you can't ignore or avoid.