Mandela is to be commended for one thing most of all...
When aparthied started to collapse, he could have easily let South Africa fall into absolute anarchy and catastrophic racial violence.
He didn't let that happen. His word carried enough weight that it largely prevented widespread violence.
Hoping that this doesn't create a Singularity, but I have to agree with Mike once again.
All one has to do is look at the experience of other African nations (Rhodesia/Zimbabwe or the Congo anyone) for examples. When they finally got rid of their colonial/white rulers, that things went all pear shaped and it was open season on, not only any whites remaining, but minority tribes, and any one who worked with/for the former .gov.
Mandela prevented that and did provide a smooth transition with almost zero bloodshed. For doing that, he truly did earn the Nobel Peace Prize. Unlike many others who, IMNSHO, have not.