Um hi, not wanting to completely put you off or anything, but I am South African.
The crime is well...very bad in all parts, its just worse in some parts thatn the others. However crime is not confined just to the city centres! DO NOT BE FOOLED!
What I can tell you is that the crime is less bad near the areas of Cape Town and Durban, than in Johannesburg. A good school to go to would be 43rd Air school, they have a website, can't remember what it is but if u search for it you will find it.
Genreally the standard of flying is to a very high standard (an It has been kow for South African piltos and engeneers to be well sought after, Especially SAAF pilots and engeneers...SAAF standing for South African Air Force)
The rand is currently around R18 to your £1 which is very good!
Also I would say that you do want to be careful what you do and where you go, try hook up with some of the SA guys at the school, they will give u the best gen. about that sorta stuff.
Good luck though and if u have anything u want to ask me feel free, just send me an email or something.
RAF TopGun