I live in Cape Town, Southern suburbs. Public transport is perfectly do-able on certain routes, and very cheap. I deliberately bought within walking distance of a railway station and the school I wanted for DD. The Southern Suburbs railway line is one of the safest, a good presence of security guards on the stations, and guards and police on trains during peak hours - it goes into central CPT one way, and down to Muizenberg and onwards the other way. Fine for day to day travel, but if I had an important appointment I would probably use the car (and allow for traffic!).
Buses possible, but less frequent and slow. Minibus taxis the most frequent, and I've never had a problem, but some are aggressive drivers, and they have a financial incentive to go as fast as possible. Having said that, the Southern Suburb stretch (along Main Road/M4) is so busy it is stop and go and little chance to get up much speed.
Take the security scares with a pinch of salt. I work in the NGO sector and have been working in the townships regularly (and using public transport to get there) for nearly 10 years without ever having any problems. Of course, you can never guarantee, and I don't wander round places I don't know or at night. But I wouldn't do that in London. In fact, the less likely you are to see another white person, the more people look out for you, are interested in why you are there etc!
SACS is a government school, but one of the historical ones, more like a private school regarding in-take. Lots of emphasis on the sons of Old Boys.
DD goes to an 'ordinary' former Model-C (whites only under apartheid) school, now with a great mix (some are still very white) and co-ed. Very similar to the good local state school I went to in rural-ish UK. Classes of about 27-30 (primary school), experienced teachers, specialist teachers for music, IT and sport. After-school sports and music clubs for those who are keen, plus various community/responsibility/volunteering opportunities. Plenty of outside space for breaktime and sports. An IT room and library, wood panelled school hall (!) for assembly, school plays and concerts. A full and part-time counsellor, and remedial teacher; psychologist and physio once a week and access to Education Dept OT (no extra cost). School fees approx. R20,000 per year, and after-care club for R600 per month up to 6pm, where they do their homework, and have some art/games activities and free play. The after-care club operates full time in the holidays, except for about 4 weeks at Xmas.
Depends what you want for DC, but I like the fact that is well resourced without being 'precious' or selective.
We have a 2-bedroom flat in a security complex, so bottom end of the range of 'middle-class' housing - not what you would think of as 'ex-pat' housing, and not what is generally thought of here as 'white' (still a huge marker, unfortunately) - on the border of a formerly white and formerly coloured area. But I love it. 24 hour security, so I feel completely safe as a single parent. In 3 years no security incidents. Shared tennis court and swimming pool, and outside space for DD. Loads of other children her age, so always someone to play with/fall out with/make up again. Safe enough for them to play hide and seek in the dark :) It's a well run complex, so rules about no loud music etc are enforced, and the maintenance is good. the value of the flat is about R700 000, levy and rates approx. R1 000.
Anyway, this has been a long ramble! But I love it here, the quality of life is wonderful, even without much money (by UK standards). Of course, it depends on what you want for your lifestyle. But before I adopted DD I used to sail every weekend as people are always looking for crew, went hiking with a hiking club, I eat out more than I could in the UK (and there is lovely wines that cost half the price!), and can afford a cleaner.
PM if you'd like any specific info :)