I have been to SA 20+ times and have never had any problem. Same as anywhere... use common sense and you will be fine.

I do notice quite a difference between Joberg and Cape Town though with Cape Town being the better of the two.

SA has got to be one of the most beautiful countries in the world. It would be a shame if someone had the opportunity to visit and didn't because of their fear of being murdered/raped/hijacked/etc.