Having lived in the US and UK for over 7 + years, doing IT, I can tell you that you learn way much more here than you do over there. I worked in central London and Wall Street in NY and the jobs they have over there are NOTHING compared to the experience you get in SA. When I came back, mostly because of the awful weather, I really thought I was it, damn I was wrong. But rather go over, meet new people, have fun and then most likely you will realize what an awesome life we have over here.
I am sure this may have been your experience, but I completely disagree with this generalization. I work as a software engineer / quant, and have found the caliber of software engineering / quant work as well as general IT to be much higher in both the UK and USA (especially) than in SA. I expect that the reason for this disparity is that the quality of the IT and Engineering staff is far more closely tied with the culture of the particular company and even sub-division of the company (for large companies), than it is to the country it resides in. So to the OP: Choose your employers carefully, since YMMV.
To the OP on the topic of "should I stay or should I go": I strongly suggest going overseas as soon as possible. Here's why:
If you wait for a 5/10/20/etc. year time frame, you will be going overseas, likely to a more junior job, because of your relatively low (by 1st world international standards at least) SA salary, and with far less cash in your pocket. You will then have to live in a country that is very expensive, and experience a sharp decrease in your standard of living (which may eventually be amortized, but it will still be hard).
If you go soon, you will likely either hate it or love it. If you love it, you will stay, and you would have made the right decision. If you hate it, you will come back to SA, but hopefully with a lot more savings, a higher salary to negotiate at more senior role with in SA, and a bunch of new experiences.
I am currently in the USA (nearly 10 years now), and have worked in South Africa, and both Silicon Valley and Wall Street (US and UK offices). I went the work route, and got a job offer, visa, green card, etc. It's was a long process, but worth it.
AFAIK, almost all 4 year BSc degrees (4 year, or 3+hons) are recognized in the US and UK, same with MSc and PhD degrees. There are organizations that publish official education equivalence documents, which are used as justification for hire during your visa application process - when you are accepted by an overseas company, they will use an immigration attorney to get all the documents together for the application. Usually, right at the beginning, either an experienced HR person at the company or the immigration attorney, will know offhand if there are issues with your qualifications. I have never heard of this being an issue with a university degree (I have heard of on issue with a B.Tech degree, although even that eventually did get through successfully - there were a lot questions along the lines of: what is a "B.Tech"? If it's the same level as a BSc, then why is it called something different? If it's more practical then a BSc, then why is it a degree and not a diploma? etc.). The US also tends to treat 3 years of experience as 1 year of study, so if you have a 3 year degree and 3+ years of experience you will be eligible, also if you have no degree and have 12+years experience, you will be eligible for a work visa. The biggest obstacle after receiving a job offer is usually immigration quotas. Your chances are still good, but would be much higher with an MSc or higher degree.
But my main idea was to go for a short holiday there, maybe with some friends and spend that time going around the different states to find out if I'd first even like to live there 
