Last year, on a visit to South Africa, I was able to visit the tower at JNB. I was also introduced to the ATC folks.
Talking to the woman on the position that covers the East/South Atlantic, pretty much from the 'bulge' down to Cape Town. She said that European crews were always very pleased to hear them! This may well have something to do with the professional approach of the controllers elsewhere in that continent!
I am sure that Guv can give us his experiences of African ATC!