Here is the most important difference: When Nelson Mandela became President of South Africa, he did not yell out, "We won, hahahahah, we won - you lost," to the whites. Mandela worked with the once-hated opposition and believed in reconciliation. Obama of course, will not even sit down with Republicans on any matter and merely treats them as annoying pests:

The Foundry: Conservative Policy News Blog from The Heritage Foundation, 23 Apr 2012, New York Times Finally Notices Obama's Unilateral Abuse of Power

Today’s New York Times offers a stunning revelation for anyone who hasn’t been following the news out of Washington for the past three years: President Barack Obama is bypassing Congress and using his executive authority to unilaterally implement his policies of choice, irrespective of the will of the people.

The Times cites an episode last fall when the president declared in a White House meeting “that the administration needed to more aggressively use executive power to govern in the face of Congressional obstructionism.” And so was born the president’s “We Can’t Wait” slogan, which has become a mantra for the Obama Administration’s unilateral form of governance. The Times overlooks the fact that the president’s “new” slogan had been conceived and implemented well before last fall.

After the November 2010 elections, the president — who was suddenly facing a Republican majority in the House after having enjoyed two years of Democrat rule — now had no choice but to compromise with the opposition party if he wanted to get things done legislatively. The thing is, the president didn’t want to compromise — he wanted to enact his agenda. And so he admitted quite plainly that where he could not legislate, he would regulate and do an end run around Congress.

Yes, Obama is a smooth talker, a sweet-talker, but as the old saying goes: "You can roll a turd in powdered sugar and call it a truffle, but it's still going to taste like shit."