It's good that you're thinking of making the jump. What exactly do you want to do with the rest of your working life? Coast? I doubt it. Also, if you're working for the Green Giant, I would hardly worry about having to be an incredibly efficient worker.
I have lived in Cape Town (2.5 years) and Joburg (say over 20 years), and I choose Cape Town any day of the week. This place is cosmopolitan, well run (go DA), clean, close to beaches, that flippin mountain, wine farms and so on. As someone else mentioned Cape Town has alot of "individual secrets" - in Joeys everything feels so standardised and corporate. Here you'll find some of the best Coffee Shops in the country (the best I'd wager), fashion etc. There is also more than one employer here. So even if you got fired, you'd find another job. There are less jobs some say, but in the same light, also less competition.
Man up and do it!