This is the kind of opportunity, barring what Coppertop warned about and having the company screw you or getting caught by an IED, that normally comes for people once in a lifetime.
Personally I'd jump at the chance, though with my record I couldn't pass a clearance and I don't know if I would leave my kids for a full year. You mentioned getting 8 weeks of vacation, could you come home and see the SO? Or with all the money you could meet her in some of those vacation destinations like Paris and Rome
Maybe I'm being entirely too monetary in the way that I look at it, but honestly, if I were you I'd go, though you may have more to lose than I do.