I voted Africa, being from South Africa. When I clicked on the up-arrow, the number of points did not increment immediately. I had to refresh the page to see the new number of points. Poor user experience.
More than Joburg, methinks. You have Silicon Cape, Google Ventures, topless models, great mountain biking and a local government that has some interest in your continued success.
Having lived in both Cape Town and Joburg (presently), I've noticed an interesting difference between the city cultures. People in Cape Town seem to start up creative and popular but small businesses, whereas people in Joburg seem to leverage off the huge business network here to create more 'serious', traditional businesses that tend to be more profitable but less 'cool' or popular.
Furthermore, in Cape Town it was rare for me to actually meet people interested in doing a startup whereas in Joburg EVERYBODY wants to know what you do, who your contacts are, if you're keen to get in on something, etc. I'm actually a bit overwhelmed here by opportunities compared to Cape Town.