I'd take the lump sum. In essence the alternative is equivalent to getting a ~5.2% annual return guaranteed... except that nothing in life is really guaranteed. Times change and who is to say what the state of the issuing authority will be in 10, 20, 50 years? I'd rather have the full amount under my control than always wondering if some unrest or collapse of government will lead to a loss of income.
Plus, it's just not that hard to earn over 5% with the million dollars if you can bear some amount of risk.