In my opinion South Africa is the African country with the best stable and standard league. I might be wrong because I am not exposed to many other African leagues become of their exposure so for me it is South Africa.
The South African league has developed so well, quite a lot of money has been pumped into their league and how well it is growing is evident for everyone to see. That said, if we are talking of the best league in Africa, i would still say it is the Egyptian league, because it is their teams that top the rankings of CAF champions league winners and it is also great that many of the players that represent their national team play their club football in Egypt.