How much flying will you be doing, and with which airlines, and in which classes? And in which regions of the world will you be redeeming? For flights or upgrades? these are the kinds of things you need to figure out before you commit to a FFP...
by the by, if you're moving to jersey, you might want to jump to continental, just for ease of nonstop flights from EWR... And they do fly nonstop EWR to ARN/CPH/OSL.