Although it is still the case that the majority of immigrants to South Africa come from nearby neighbours such as Zimbabwe and similar countries, it is also true that there is a long standing tradition of immigration to South Africa from the European Union. In fact, South Africa was settled by the Europeans in the 17th and 18th centuries, and there are many people in the country who descend from those early immigrants. During the heavy years of Apartheid, there was a reduced number of immigrants from the EU, but in the years afterwards there has been a steady influx of European nationals looking to settle in South Africa.
Part of the reason why so many people feel that European immigrants are more successful in moving to South Africa is that the country feels a sense of unity with Europe, perhaps even a sense of yearning to be a part of a European nation again. South Africa has lots of European heritage, reflected most clearly in the two public and political languages, English and Afrikaans, with the later closely connected to the Dutch immigrants who first settled in the country over 300 years ago.
Some people have suggested that the reason that the European immigrants are so successful is due to the lasting impact of Apartheid, but perhaps a stronger reason is that South Africa has tried to limit the number of unskilled workers who are moving to the country. The workers allowed to immigrate tend to be civil engineers and bio-chemical experts who can help the country to build up its technological industries, and improve its mining and agricultural elements too. Europeans are likely to come from good universities, and to have acquired the skills needed in South Africa, and this also makes them popular with companies.
In addition, European settlers have the advantage of a reduced exchange rate which makes their pensions or private incomes worth much more in South Africa than they are in their own European cities. With living costs also much cheaper, Europeans tend to be less conservative with their cash, helping the South African economy. Many parts of the capitals in South Africa have been developed so that they look somewhat like a Western city, with large skyscrapers not a few miles from historic settlements and urban areas. This not only appeals to the Europeans, but also makes them able to connect with the culture of those cities, having experienced the same mix of innovative and historical in their own cities.
The combination of mutual language and culture, plus the ability to fit into the South African way of life, means that Europeans already have an advantage over most of the other immigrants in the country. The fact that they are likely to have the skills which South African industry and technology needs also means that they are more likely to find success on immigration to South Africa, and adopt the latter country as their residence on a permanent basis.