Following, as we're headed to SA at the end of December.

<<I figure it's like any big city>>

It's not really like any other big city, you do need to take much more care in JNB than you would in NY for instance. I would not walk around at night anywhere, except Sandton Mall and even walking between the Bull Run and Sandton Mall at night is not entirely comfortable. I would not drive at night either (Cape Town is ok though.)
Whilst nothing has happened to me (except some guys who decided to sit on my rental car hood whilst stopped at the traffic lights (robots) asking for money), I know things do happen, I have relatives who have lived in JNB & CPT for 30/40 years plus I have spent a lot of time on business in JNB and have heard colleagues experiences too. Whilst the stories might be exaggerated or old news, there is truth in them and I take their advice. On business trips, I was not even allowed to walk from my hotel to the office which was literally across the road, I had to use the company driver. On my daughter's last trip back from South Africa (2 years ago approx), on the flight home, she sat next to an elderly couple whose husband had been shot on the last day of their 3 month stay, during a robbery of their rental home.

bookmarking - lots of great information here

Thanks, Odin. Sounds pretty terrible; I will take extra care.