Politically and economically the country is fairly safe. The economy is closely linked to that of South Africa with the Nam $ pegged to the South African Rand. The economy itself is fairly healthy and growing steadily at around 4%GDP anually.
as far as personal safety is concerned - well lets just say that its not advisable to leave valuables lying around. Common sense is a pre requisite.
Is the flying safe - well if you're looking for perfect safety you best be a bird and sit on a fence! (it goes something like that)
I think that there are certainly aspects of the Namibian aviation industry that are not up to par. However I am lead to believe that most pilots in Namibia are not perminent residents (and therefore mostly foreign) yet they all seem to have a good time and get a few hours. There does seem to be a fairly strong demand for german speaking pilots (that is with certain companies anyway).
As for the health system - apart from the recent outbreak of polio, 25% of the population with HIV/AIDS, malaria in the north, and a high incidence of TB - its OK! (But hey this is Africa so such diseases are fairly prevelant throughout the region) Once again common sense is a pre requisite - washing fresh food and personal hygeine etc. However private health care is seriously worth considering.
Apart from that it has to be said that it is certainly a beautiful country. Dense wodlands and swamps in the North (Caprivi), the deserts along the coast, the 2nd largest canyon in the world, as well as the infamous Etosha national park. They say if it can't be done in Namibia its probably not worth doing!