Bitcoin is better than gold, as long as the NSA doesn't bring a few gazillionhashes/sec with an ASIC farm they own to gain 51% the network. All it'd take for the NSA is a ~50-100mn USD equipment contract with some ASIC manufacturer (which is peanuts for their standards).

Gold has no 51% attack problems or external uncertainties of what the NSA will do tomorrow. It has however other types of uncertainties like what will happen to gold production if the energy prices are somehow down by 80-90%, or what will happen if underseas mining start, or what will happen if gold can, at some point, by synthesized by low energy nuclear reactions etc.