In my experience as a general rule of thumb if there is a multi national chain hotel go for it - SA can't go too wrong in the larger cities with a lot of choices, in smaller places as it goes Africa is Africa.
Don't expect a Shereton anywhere in Africa to be like the Shereton Sydney etc but it does the job better then great considering. Just don't drink out of the taps.
Most larger airports with a good RPT international operation have a decent hotel adjacent with a bar your sure to bump into someone if you've done the rounds through the place.