What is special about Illy coffee?

So, what sets Illy coffee apart from the rest of the pack? Is it the unique blend of beans they use? Or is it the precision with which they roast and grind their coffee? Do they have some sort of secret ingredient that gives it that extra special flavor? I'm curious to know what makes Illy coffee so special and sought after by coffee lovers around the world. Is it just a matter of taste, or is there something more to it?