Goose,
I've flown SAA BC several times and had vastly different experiences to Cheetah; albeit it was 3 years ago now.
On 4 return trips to JNB I could not fault SAA, their crew, their service or visible safety. I think I was on a 747 and the seats were excellent; leg room was exceptional. I did not choose SAA, this was done for me and I had did have reservations before travelling, all unfounded - other than JNB is possibly the worst airport I have to go through.
My last trip with BA over the pond was OK, nothing special and certainly the crew were not anything special.