In the past JNB has had problems, but these appear to be solved in the past year. They have a heavy police presence now. The problem was organized gangs who would steal unattended suitcases (or pretend to be airport employees and steal your suitcase). Also pickpockets. So the stories are true but don't apply to the current airport, which is as safe as US airports. The shopping is good in terms of selection but prices are high now (in USD) due to the rise in the rand's value. When you leave the airport be aware that crime is a problem in many areas (you will see lots of security guards at shopping mall entrances, for example, and they are there for a reason). Also if you are driving, carjacking is a problem in some parts of town and running a red light at a robot is allowed in the law (it is that bad of a problem at times). The crime rate is much worse than any US city at its worst, however with reasonable precautions you won't see any of it.