If we are going to talk about the crime issue alone we will end up painting a very negative picture of SA.
I think the key difference between South Africa and say the UK is that life is cheap in Africa. In the UK most muders are not random affairs - they are either gang or drug related, or crimes of passion, perversion or revenge. In SA a great deal of murder occurs in the course of other crimes such as robbery, mugging and hijackings. Its not uncommon also for women to be raped during the course of house burgalry. The criminal justice system is also a joke. So most are never caught & those that are, will either escape punishment or just plainly escape from custody.
But to me the decision isn't just about crime. The UK for instance is an overcrowded island - just a fifth the size of SA but with about another 20m people. Your average Brit spends most his time working hard to pay his mortgage and then most of his leisure time getting pissed in the pub in between complaining about the weather, the government and why we never win at sport (fingers crossed that might change). Traffic congestion is also a nightmare. In SA there is an infinitely better quality of lifestyle available. Other than first class sports & leisure, restaurants are actually staffed with people that are pleased to serve you, and the food is much better. School children actually know how to behave and respect other people.