I'm a minority. I dont really find either really offensive. Depends more on whos mouth it comes from and what actions are a result against it. I find people who resort to ethnic insults a result of that they can't really think of something better to insult me with. I say dont insult a man because of the color of his skin. Insult the man because he's an idiot.
Oddily enough I find more minorities have a pinch if not full fledged racism and alot of whites are more offended by things dealing with racism.